As filed with the Securities and Exchange Commission on January 23, 2014

Registration No. 333-193131

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

AMENDMENT NO. 1

TO

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ELEVEN BIOTHERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware

2834

26-2025616

(State or other jurisdiction of incorporation or organization)

(Primary Standard Industrial Classification Code Number)

(I.R.S. EmployerIdentification Number)

215 First Street, Suite 400

Cambridge, MA 02142

(617) 871-9911

(Address, including zip code, and telephone number, including area code, of registrants principal executive offices)

Abbie C. Celniker, Ph.D.

President and Chief Executive Officer

Eleven Biotherapeutics, Inc.

215 First Street, Suite 400

Cambridge, MA 02142

(617) 871-9911

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies
to:

David E. Redlick, Esq.

Brian A. Johnson, Esq.

Richard A. Hoffman, Esq.

Wilmer Cutler Pickering Hale and Dorr LLP

60 State Street

Boston, Massachusetts 02109

(617) 526-6000

Brent B. Siler, Esq.

Andrew S. Williamson, Esq.

Brian F. Leaf, Esq.

Cooley LLP

11951 Freedom Drive

Reston, Virginia 20190

(703) 456-8000

Approximate date of commencement of proposed sale to public: As soon as practicable after this Registration Statement is declared effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, check the following box. ¨

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the
following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment filed pursuant to
Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same
offering. ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller
reporting company. See the definitions of large accelerated filer, accelerated filer and smaller reporting company in Rule 12b-2 of the Exchange Act.

Large accelerated filer ¨

Accelerated filer ¨

Non-accelerated filer x

Smaller reporting company ¨

(Do not check if a smaller reporting company)

CALCULATION OF REGISTRATION FEE

Title of Each Class of

Securities To Be Registered

Proposed

Maximum

Aggregate

Offering Price(1)

Amount ofRegistration Fee(2)

Common Stock, $0.001 par value per share

$74,175,000

$9,554

(1)

Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(o) under the Securities Act of 1933, as amended.

(2)

Calculated pursuant to Rule 457(o) based on an estimate of the proposed maximum aggregate offering price. A registration fee of $8,888 was previously paid in
connection with the Registration Statement, and the additional amount of $666 is being paid herewith.

The
Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall
thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these
securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting offers to buy these securities in any state or other
jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED JANUARY 23, 2014

PRELIMINARY PROSPECTUS

4,300,000 Shares

Eleven Biotherapeutics, Inc.

Common Stock

$ per share

This is the initial public offering of our common stock. We
are selling 4,300,000 shares of common stock in this offering. We currently expect the initial public offering price to be between $13.00 and $15.00 per share of common stock.

We have granted the underwriters an option to purchase up to
645,000 additional shares of common stock to cover over-allotments.

We have applied to list our common stock on The NASDAQ Global Market under the symbol EBIO.

We are an emerging growth
company under applicable Securities and Exchange Commission rules and will be eligible for reduced public company disclosure requirements. See SummaryImplications of Being an Emerging Growth Company.

Neither the Securities and Exchange Commission nor any state
securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Per Share

Total

Public Offering Price

$

$

Underwriting Discount(1)

$

$

Proceeds to Eleven Biotherapeutics, Inc. (before expenses)

$

$

(1)

We refer you to Underwriting beginning on page 158 for additional information regarding underwriting compensation.

Certain of our preferred stockholders, including our existing
principal stockholders, and their affiliated entities have indicated an interest in purchasing an aggregate of approximately $12 million in shares of our common stock in this offering at the initial public offering price. However, because
indications of interest are not binding agreements or commitments to purchase, these stockholders may determine to purchase fewer shares than they indicate an interest in purchasing or not to purchase any shares in this offering. It is also possible
that these stockholders could indicate an interest in purchasing more shares of our common stock. In addition, the underwriters could determine to sell fewer shares to any of these stockholders than the stockholders indicate an interest in
purchasing or not to sell any shares to these stockholders. The underwriters will receive the same underwriting discount on any shares purchased by these entities as they will on any other shares sold to the public in this offering.

The underwriters expect to deliver the shares to purchasers
on or about , 2014 through the book-entry facilities of The Depository Trust Company.

We are responsible for the information contained in this prospectus. We have not
authorized anyone to provide you with different information, and we take no responsibility for any other information others may give you. If anyone provides you with different or inconsistent information, you should not rely on it. We are not, and
the underwriters are not, making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date
on the front of this prospectus.

This summary highlights information contained elsewhere in
this prospectus. This summary does not contain all of the information you should consider before investing in our common stock. You should read this entire prospectus carefully, especially the Risk Factors section and our financial
statements and the related notes appearing at the end of this prospectus, before making an investment decision.

Company Overview

We are a clinical-stage biopharmaceutical company with a proprietary protein engineering platform, called AMP-Rx, that we apply to the discovery and development of protein therapeutics to treat diseases
of the eye. Our therapeutic approach is based on the role of cytokines in diseases of the eye, our understanding of the structural biology of cytokines and our ability to rationally design and engineer proteins to modulate the effects of cytokines.
Cytokines are cell signaling molecules found in the body that can have important inflammatory effects. We believe cytokines play a major role in the pathology underlying many eye diseases and that protein therapeutics are an effective means of
modulating the effects of cytokines in diseases of the eye. We have used our AMP-Rx platform to rationally design, engineer and generate a pipeline of innovative protein therapeutic candidates that target cytokines we believe are central to diseases
of the eye. We are conducting research and development programs directed at both diseases of the front of the eye, such as dry eye disease and allergic conjunctivitis, and diseases of the back of the eye, such as diabetic macular edema, or DME, and
uveitis.

Our most advanced product candidate is
EBI-005. We designed, engineered and generated EBI-005 using our AMP-Rx platform and are developing EBI-005 as a topical treatment for dry eye disease and allergic conjunctivitis. Our EBI-005 program is based on the role that elevated levels of the
inflammatory cytokine interleukin-1, or IL-1, play in the initiation and maintenance of the inflammation and pain associated with dry eye disease and the redness and itching associated with allergic conjunctivitis. We hold worldwide
commercialization rights to EBI-005.

In 2013,
we completed a Phase 1b/2a clinical trial of EBI-005 in patients with moderate to severe dry eye disease. We believe that the results of this trial, together with the results of a separate Phase 1/2 clinical trial conducted by one of our scientific
co-founders using another IL-1 receptor antagonist in patients with moderate to severe dry eye disease and published in the peer-reviewed journal JAMA Ophthalmology in 2013, support our initiation of a pivotal Phase 3 clinical program
evaluating EBI-005.

Our planned pivotal Phase 3
clinical program will consist of two Phase 3 clinical trials evaluating the safety and efficacy of EBI-005 for the treatment of moderate to severe dry eye disease and a separate clinical trial evaluating the safety of treatment with EBI-005 for one
year. Based on our estimates regarding patient enrollment, if this clinical program is successful, we plan to submit a Biologics License Application, or BLA, to the U.S. Food and Drug Administration, or FDA, seeking approval of EBI-005 for the
treatment of dry eye disease in the United States in the second half of 2016. We also plan to initiate a Phase 2 clinical trial to evaluate the use of EBI-005 in patients with allergic conjunctivitis in early 2014. We believe that the net proceeds
from this offering, together with our existing cash and cash equivalents, will be sufficient to fund both our Phase 3 clinical program evaluating EBI-005 for the treatment of dry eye disease and our Phase 2 trial evaluating EBI-005 for the treatment
of allergic conjunctivitis.

Our preclinical
product candidates include EBI-029 for the treatment of DME, a serious disease of the central portion of the retina known as the macula, and EBI-028 for the treatment of uveitis, which is an inflammatory disease of the middle layer of the eye known
as the uvea. We plan to continue to study both EBI-029 and EBI-028 in preclinical models to further optimize these product candidates for potential use in humans.

The following table summarizes key information about our product development programs.

We are led by a
management team with extensive experience in the pharmaceutical industry. Our President and Chief Executive Officer, Abbie C. Celniker, Ph.D., brings more than 20 years of experience in leading protein therapeutic discovery and development companies
and programs. The cornerstone of our biological approach is based on the research of one of our scientific co-founders, Dr. Reza Dana, who is currently a Professor of Ophthalmology and the Claes Dohlman Chair in Ophthalmology at Harvard Medical
School. Our principal investors are funds managed by Third Rock Ventures, LLC, Flagship Ventures Management, Inc. and JAFCO Co. Ltd.

Our Approach

Until recently, ocular therapies generally have been developed based on a limited understanding of the biology underlying the initiation
and maintenance of the disease state. As a result, many of the therapies for eye diseases were not the result of rational drug design, but instead were ophthalmic formulations of pharmaceuticals that were originally developed and approved for
non-ocular diseases, such as steroids and antihistamines. We believe that this limited understanding of the biology of eye diseases impeded the discovery and development of innovative ophthalmic therapeutics.

Over the past 15 years, researchers have been developing a
greater understanding of the key proteins and pathways involved in ocular disease. For instance, the understanding of the protein pathways involved in the retinal disease wet age-related macular degeneration, or wet AMD, has led to the successful
development of drugs such as Lucentis and Eylea that have dramatically improved the outcomes for many patients. We believe that we can apply similar advances in the understanding of other protein pathways involved in eye diseases to the discovery
and development of new treatments for these diseases.

We apply a rational, biology-based approach to the discovery and development of novel protein therapeutics for patients suffering from eye diseases. Our therapeutic approach is based on the role of
cytokines in diseases of the eye, our understanding of the structural biology of cytokines and our ability to rationally design proteins to modulate the effects of cytokines.

AMP-Rx is our proprietary platform that we use to design, engineer and generate novel
protein therapies that modulate key molecular targets we believe are responsible for the initiation or maintenance of an ocular disease. We begin by analyzing the target and identifying the protein-based approaches we may use to modulate the target.
We then generate protein candidates and model protein/target interactions to inform an iterative protein optimization technique. We use this process to modify protein drugs to meet design specifications for improved biological and drug-like
properties. We have established a collaboration with ThromboGenics, N.V., or ThromboGenics, in which we apply our AMP-Rx platform to design and engineer innovative ophthalmic medicines.

Dry Eye Disease

Dry eye disease affects the ocular surface and is characterized by symptoms of dryness, pain, discomfort and irritation. If dry eye
disease is left untreated or becomes severe, patients may suffer chronic ocular pain and distortion of vision that can significantly reduce their quality of life. Dry eye disease often is classified as mild, moderate or severe based on clinical
symptom severity. Dry eye disease is one of the leading causes of patient visits to eye care professionals in the United States. According to Market Scope, LLC, or Market Scope, a publisher of research and analysis on the ophthalmic market,
approximately 68 million people in the United States, European Union, Japan and other developed markets have dry eye disease, including approximately 26 million people who suffer from the moderate to severe form of dry eye disease. According to
Market Scope, approximately 19 million people in the United States have dry eye disease, including approximately seven million people who suffer from the moderate to severe form of dry eye disease.

The current standard of care for moderate to severe dry eye
disease includes artificial tears and topical anti-inflammatory and immune-modulating drugs. The anti-inflammatory and immune-modulating drug market for the treatment of moderate to severe dry eye disease consists primarily of Restasis, which is
approved for use in the United States, and off-label use of corticosteroids. Restasis, which had annual worldwide sales of approximately $792 million in 2012, is not approved for the treatment of the symptoms of dry eye disease, but only for
increasing tear production in patients whose tear production is presumed to be suppressed due to ocular inflammation associated with dry eye disease. In clinical trials, approximately 17% of patients reported ocular burning following the use of
Restasis. We believe that there remains a significant unmet medical need for new treatments for patients suffering from moderate to severe dry eye disease.

EBI-005  a Novel IL-1 Receptor Antagonist

Our most advanced product candidate is EBI-005, a recombinant protein which binds with the IL-1 receptor and blocks, or antagonizes, IL-1
receptor signaling on many cell types in the eye. We are developing EBI-005 as a topical, eye-drop treatment for dry eye disease and allergic conjunctivitis. When the IL-1 receptor is blocked by EBI-005, the IL-1 receptor is unable to transmit the
biological signals that we believe are responsible for many of the signs and symptoms of ocular surface diseases, such as pain, discomfort, itching and inflammation. We have designed, engineered and generated EBI-005 using our AMP-Rx platform to
have the following product attributes that we believe improve its utility as a topical therapeutic:



Rapid onset of action. We have designed EBI-005 to be a potent blocker of IL-1. In a biochemical study of receptor binding, EBI-005 bound more
rapidly and up to 500 times more strongly to the IL-1 receptor than the natural ligands IL-1ß and IL-1Ra. We believe this may result in a rapid onset of symptomatic relief.



Comfortable for patients. We have optimized EBI-005 for topical, ophthalmic delivery and have formulated it with a preservative-free comfortable
solution, or vehicle, for delivery as an eye drop. We believe patient comfort is an important factor in patient compliance and physician recommendation of a topical drug for diseases of the ocular surface.



Convenient dosing. We have designed EBI-005 to bind tightly to the IL-1 receptor and block it for an extended period of time. We have measured
the duration of this receptor binding in biochemical studies

outside the body, or in vitro. Based on these tests and our understanding of the natural cycling of the IL-1 receptor from the cell surface to the
cell interior, we believe EBI-005 remains bound to an IL-1 receptor during the entire period the receptor is present on the surface of a cell. We believe a long duration of receptor binding may allow for a convenient dosing schedule.



Stable dosage form. We designed EBI-005 to be a thermally stable protein product. In analytical tests, EBI-005 was stable for at least five
months at room temperature. We believe room temperature stability without the need for refrigeration is an important convenience for patients.

In 2012, we submitted an investigational new drug application, or IND, to the FDA for purposes of conducting clinical trials of EBI-005
for the treatment of dry eye disease. In 2013, we completed a Phase 1b/2a clinical trial of EBI-005 in patients with moderate to severe dry eye disease. We designed our Phase 1b/2a clinical trial of EBI-005 principally to assess safety in dry
eye disease patients and secondarily, to measure efficacy in order to inform the design of our pivotal clinical trials. In our Phase 1b/2a trial, EBI-005 was generally well tolerated. While we did not power our Phase 1b/2a trial to measure efficacy
with statistical significance, and the differences from baseline that we observed in the EBI-005 treatment groups were not statistically significant when compared to differences from baseline in patients who received vehicle control, we observed the
following results, among others, in this trial:



on the primary efficacy endpoint of change in patient symptoms as assessed by a patient questionnaire called the ocular surface disease index, or OSDI,
an improvement in patients treated with EBI-005 from baseline at six weeks;



on the secondary efficacy endpoint of change in total corneal fluorescein staining, or CFS, a measure of ocular surface injury, an improvement in
patients treated with EBI-005 from baseline at six weeks;



on the painful or sore eyes question of the OSDI, a greater improvement from baseline at six weeks in patients treated with EBI-005 compared to
improvement from baseline at six weeks in patients in the vehicle control group; and



fewer artificial tears used by patients treated with EBI-005 compared with patients in the vehicle control group, and this difference was statistically
significant.

We believe these results were
clinically relevant.

Our planned pivotal
Phase 3 clinical program will consist of two Phase 3 clinical trials to evaluate the safety and efficacy of EBI-005 from baseline at 12 weeks at a concentration of 5 mg/ml for the treatment of moderate to severe dry eye disease and a separate
clinical trial evaluating the safety of treatment with EBI-005 at the same concentration for one year. We have designed our pivotal Phase 3 clinical program based on the results we observed in our Phase 1b/2a clinical trial of EBI-005. We have begun
screening patients for our first Phase 3 trial and expect to begin randomizing and treating patients in this trial by early February 2014. Based on our estimates regarding patient enrollment, we expect to have top-line data from our first Phase 3
trial available in early 2015. We currently intend to initiate our second Phase 3 trial after reviewing top-line data from our first Phase 3 trial, although we may later decide to initiate our second Phase 3 trial while our first Phase 3 trial is
ongoing. If the results of both of our Phase 3 trials and our separate safety trial are favorable, we plan to submit a BLA with the FDA seeking approval of EBI-005 for the treatment of dry eye disease in the United States in the second half of 2016.

In addition to our clinical development of
EBI-005 in dry eye disease, we plan to initiate a Phase 2 clinical trial in early 2014 of EBI-005 in patients with allergic conjunctivitis who have not responded adequately to antihistamines or mast cell stabilizers. In December 2013, we submitted a
clinical trial application to Health Canada for purposes of conducting clinical trials of EBI-005 for the treatment of allergic conjunctivitis. Allergic conjunctivitis is an inflammatory disease of the conjunctiva, the membrane covering the inside
of the eyelids and white part of the eye, primarily from a reaction to allergy-causing substances such as pollen or pet dander.

Our goal is to become a leading biopharmaceutical company
focused on developing and commercializing novel protein therapeutics to treat diseases of the eye. The key elements of our strategy in support of this goal are to:



Complete clinical development of and seek marketing approval for EBI-005 for the treatment of dry eye disease. If the results of both of our
Phase 3 trials and our separate safety trial are favorable, we plan to submit a BLA to the FDA seeking approval of EBI-005 for the treatment of dry eye disease in the United States in the second half of 2016.



Expand the use of EBI-005 for additional ocular indications. In early 2014, we plan to initiate a Phase 2 clinical trial to assess the potential
therapeutic benefit of EBI-005 for the treatment of allergic conjunctivitis in patients who have not responded adequately to antihistamines or mast cell stabilizers.



Maximize commercial potential of EBI-005. We hold worldwide commercialization rights to EBI-005 and may decide to build our own focused,
specialty sales force in order to commercialize EBI-005 in the United States ourselves. We intend to enter into strategic collaborations for the development and commercialization of EBI-005 outside of the United States.



Apply AMP-Rx platform to build a pipeline of product candidates for the treatment of eye diseases. We use our AMP-Rx platform to rationally
design, engineer and generate a pipeline of innovative protein therapeutic candidates that target cytokines that we believe are central to diseases of the eye.



Pursue collaborative and other strategic opportunities. We have established a collaboration with ThromboGenics, a European based, publicly held
biopharmaceutical company focused on developing and commercializing innovative ophthalmic medicines. We plan to evaluate opportunities to enter into other collaborations that may contribute to our ability to advance our product candidates and to
progress concurrently a range of discovery and development programs.

Risks Associated with Our Business

Our business is subject to a number of risks of which you should be aware before making an investment decision. These risks are discussed more fully in the Risk Factors section of this
prospectus. These risks include the following:



We depend heavily on the success of EBI-005. Our ability to generate product revenues, which we do not expect will occur before 2017, if ever, will
depend heavily on our obtaining marketing approval for and commercializing EBI-005.



Our Phase 3 clinical program evaluating EBI-005 may not be successful. In our Phase 1b/2a trial of EBI-005, neither of the doses of EBI-005 tested
achieved statistically significant superiority compared to vehicle control based on any primary or secondary efficacy endpoints, including those we intend to use for our planned Phase 3 clinical trials. We have based many elements of the design of
the protocol for our planned Phase 3 clinical trials, including key eligibility criteria and the co-primary endpoints we expect to use, on retrospective subgroup analyses that we performed on the results of our Phase 1b/2a clinical trial. These
retrospective subgroup analyses may not be predictive of the results of these Phase 3 trials.



We are an early stage company. We currently have no commercial products, and all of our product candidates, other than EBI-005, are still in
preclinical development.



We have not yet demonstrated our ability to successfully complete a pivotal Phase 3 clinical trial, obtain marketing approvals, manufacture at
commercial scale, or arrange for a third party to do so on our behalf, or conduct sales, marketing and distribution activities necessary for successful product commercialization. If we are unable to obtain required marketing approvals for,
commercialize, obtain

and maintain patent protection for or gain market acceptance by physicians, patients and third-party payors of EBI-005 or any of our other product candidates, or experience significant delays in
doing so, our business will be materially harmed.



We face substantial competition. There are a number of products and therapies in preclinical research and clinical development by third parties to
treat dry eye disease. Some patients with moderate to severe dry eye disease are effectively treated by the current standard of care therapies, some of which are available in generic form or offered at relatively low prices. We also would face
competition with respect to EBI-005 if anakinra, another IL-1 blocker approved for subcutaneous administration for the treatment of rheumatoid arthritis, was available commercially for the treatment of dry eye disease.



We have incurred significant losses since our inception and will need substantial additional funding. As of September 30, 2013, we had an
accumulated deficit of $52.5 million. We expect to incur significant expenses and operating losses over the next several years.

Our Corporate Information

We were incorporated under the laws of the state of Delaware on February 25, 2008 under the name NewCo LS14, Inc. We subsequently
changed our name to DeNovo Therapeutics, Inc. in September 2008 and again to Eleven Biotherapeutics, Inc. in February 2010. Our principal executive offices are located at 215 First Street, Suite 400, Cambridge, Massachusetts 02142, and our telephone
number is (617) 871-9911. Our website address is www.elevenbio.com. The information contained on, or that can be accessed through, our website is not a part of this prospectus. We have included our website address in this prospectus solely as
an inactive textual reference.

In this prospectus, unless otherwise stated or the context otherwise requires, references to Eleven,
we, us, our and similar references refer to Eleven Biotherapeutics, Inc. Eleven Biotherapeutics, AMP-Rx and the Eleven logo are our trademarks. The copyright to the Ocular Surface Disease Index and the registered
trademark Restasis are the property of Allergan, Inc. The registered trademark Kineret is the property of Swedish Orphan Biovitrum AB. The other trademarks, trade names and service marks appearing in this prospectus are the property of their
respective owners.

Implications of Being an Emerging Growth
Company

As a company with less than $1
billion in revenue during our last fiscal year, we qualify as an emerging growth company as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and we may remain an emerging growth company for up to five years.
For so long as we remain an emerging growth company, we are permitted and intend to rely on exemptions from certain disclosure and other requirements that are applicable to other public companies that are not emerging growth companies. In
particular, in this prospectus, we have provided only two years of audited financial statements and have not included all of the executive compensation related information that would be required if we were not an emerging growth company.
Accordingly, the information contained herein may be different than the information you receive from other public companies in which you hold stock.

We currently estimate that we will use the net proceeds from this offering, together with our existing cash and cash equivalents, to fund our pivotal Phase 3 clinical program for EBI-005 in
patients with moderate to severe dry eye disease and submission of a BLA for this indication, to fund our Phase 2 clinical trial of EBI-005 in patients with allergic conjunctivitis and for working capital and other general corporate purposes,
including internal research and development expenses for EBI-005, development of our preclinical product candidates and pursuit of our other research and discovery efforts.

See the Use of Proceeds section in this prospectus for a more complete description of the intended use of proceeds from this offering.

Risk Factors

You should read the Risk Factors section of this prospectus for a discussion of factors to consider carefully before deciding to invest in shares of our common stock.

Proposed NASDAQ Global Market symbol

EBIO

The number of shares of our common stock to be outstanding after this offering is based on 1,799,470 shares of our common stock
outstanding as of January 21, 2014, 8,260,444 shares of our common stock issuable upon the automatic conversion of all outstanding shares of our preferred stock upon the closing of this offering and 333,799 shares of our common stock issuable upon
the exercise of outstanding warrants held by some of our preferred stockholders, at an exercise price of $0.06 per share, which otherwise expire upon the closing of this offering.

The number of shares of our common stock to be outstanding after this offering excludes:



1,346,235 shares of our common stock issuable upon the exercise of stock options outstanding as of January 21, 2014 at a weighted average exercise
price of $3.39 per share;



30,708 shares of our common stock issuable following the closing of this offering upon the exercise of warrants outstanding as of January 21, 2014 held
by our venture debt lender, Silicon Valley Bank, at an exercise price of $6.35 per share;



1,586 shares of our common stock available for future issuance under our 2009 Stock Incentive Plan, or the 2009 Plan, as of January 21, 2014;



708,661 additional shares of our common stock that will become available for future issuance under our 2014 Stock Incentive Plan, or the 2014 Plan,
upon the closing of this offering;

14,694 shares of our common stock issuable upon the exercise of stock options to be granted under our 2014 Plan to some of our non-employee directors
on the 30th trading day of our common stock on The NASDAQ
Global Market at an exercise price per share equal to the fair market value of our common stock on the date of the grant;



56,386 shares of our common stock to be granted to the chairman of our board of directors upon the closing of this offering under our 2014 Plan
pursuant to a restricted stock agreement; and



157,480 additional shares of our common stock that will be available for future issuance under our employee stock purchase plan upon the closing of
this offering.

Unless
otherwise indicated, all information in this prospectus assumes:



no exercise of the outstanding options described above;



no exercise of the warrants held by Silicon Valley Bank;



no exercise by the underwriters of their option to purchase up to 645,000 shares of our common stock to cover over-allotments;



the automatic conversion of all outstanding shares of our preferred stock into an aggregate of 8,260,444 shares of our common stock upon the closing of
this offering;



the warrants outstanding as of January 21, 2014 held by Silicon Valley Bank to purchase 195,000 shares of our preferred stock, at an exercise price of
$1.00 per share, become exercisable for 30,708 shares of our common stock, at an exercise price of $6.35 per share, automatically upon the closing of this offering; and



the restatement of our certificate of incorporation and the amendment and restatement of our bylaws upon the closing of this offering.

In addition, unless
otherwise indicated, all information in this prospectus gives effect to a one-for-6.35 reverse stock split of our common stock that became effective on January 21, 2014.

Certain of our preferred stockholders, including our existing
principal stockholders, Third Rock Ventures, L.P., Flagship Ventures Management, Inc. and JAFCO Super V3 Investment Limited Partnership, and their affiliated entities have indicated an interest in purchasing an aggregate of approximately $12 million
in shares of our common stock in this offering at the initial public offering price. Assuming an initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, these
stockholders would purchase an aggregate of 857,143 of the 4,300,000 shares offered in this offering based on these indications of interest. However, because indications of interest are not binding agreements or commitments to purchase, these
stockholders may determine to purchase fewer shares than they indicate an interest in purchasing or not to purchase any shares in this offering. It is also possible that these stockholders could indicate an interest in purchasing more shares of our
common stock. In addition, the underwriters could determine to sell fewer shares to any of these stockholders than the stockholders indicate an interest in purchasing or not to sell any shares to these stockholders. The underwriters will receive the
same underwriting discount on any shares purchased by these entities as they will on any other shares sold to the public in this offering.

You should read the following summary financial data together with our financial statements and the related
notes appearing at the end of this prospectus and the Selected Financial Data and Managements Discussion and Analysis of Financial Condition and Results of Operations sections of this prospectus. We have derived the
statement of operations data for the years ended December 31, 2011 and 2012 from our audited financial statements included in this prospectus. We have derived the statement of operations data for the nine months ended September 30, 2012
and 2013 and the balance sheet data as of September 30, 2013 from our unaudited financial statements included in this prospectus. The unaudited financial data include, in the opinion of our management, all adjustments, consisting of normal
recurring adjustments, that are necessary for a fair statement of our financial position and results of operations for these periods. Our historical results for any prior period are not necessarily indicative of results to be expected in any future
period, and our results for any interim period are not necessarily indicative of results to be expected for a full fiscal year.

Year EndedDecember 31,

Nine Months EndedSeptember 30,

2011

2012

2012

2013

(in thousands, except per share data)

Statement of Operations Data:

Collaboration revenue

$



$



$



$

824

Operating expenses:

Research and development

9,411

15,263

11,367

10,576

General and administrative

3,267

4,213

3,081

2,606

Total operating expenses

12,678

19,476

14,448

13,182

Loss from operations

(12,678

)

(19,476

)

(14,448

)

(12,358

)

Other income (expense):

Other income (expense), net

3

(13

)

7

(96

)

Interest expense

(151

)

(168

)

(122

)

(505

)

Total other expense, net

(148

)

(181

)

(115

)

(601

)

Net loss and comprehensive loss

$

(12,826

)

$

(19,657

)

$

(14,563

)

$

(12,959

)

Cumulative preferred stock dividends

(1,452

)

(3,111

)

(2,201

)

(2,715

)

Net loss applicable to common stockholders

$

(14,278

)

$

(22,768

)

$

(16,764

)

$

(15,674

)

Net loss per share applicable to common stockholdersbasic and diluted

$

(17.80

)

$

(22.93

)

$

(17.83

)

$

(11.87

)

Weighted-average number of common shares used in net loss per share applicable to common stockholdersbasic and
diluted

802

993

940

1,320

Pro forma net loss per sharebasic and diluted (unaudited)

$

(2.76

)

$

(1.52

)

Weighted average number of common shares used in pro forma net loss per sharebasic and diluted (unaudited)

7,118

8,539

See Note 2 within the
notes to our financial statements appearing at the end of this prospectus for a description of the method used to calculate basic and diluted net loss per share applicable to common stockholders and unaudited pro forma basic and diluted net loss per
share.

the completion of our series B preferred stock financing in December 2013 in which we issued and sold an aggregate of 7,203,845 shares of our series B
preferred stock and warrants to purchase 202,472 shares of our common stock for an aggregate purchase price of $12.6 million, consisting of $9.0 million in cash and $3.6 million for the conversion of outstanding convertible promissory notes,
including accrued interest;



the automatic conversion of all outstanding shares of our preferred stock, including the shares of our series B preferred stock that we issued in
December 2013, into an aggregate of 8,260,444 shares of our common stock upon the closing of this offering;



the reclassification of our warrant liability to stockholders equity as a result of warrants to purchase preferred stock becoming warrants to
purchase common stock upon the closing of this offering; and



the issuance of 478,061 shares of our common stock upon the exercise of outstanding warrants held by some of our preferred stockholders, at an exercise
price of $0.06 per share, including shares of our common stock issuable upon the exercise of the warrants that we issued in December 2013, which otherwise expire upon the closing of this offering.

The unaudited pro forma as adjusted balance sheet data give
further effect to our issuance and sale of 4,300,000 shares of our common stock in this offering at an assumed initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this
prospectus, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

A $1.00 increase or decrease in the assumed initial public offering price of $14.00 per share, which is the midpoint of the price range
set forth on the cover page of this prospectus, would increase or decrease each of cash and cash equivalents, working capital and total stockholders equity on a pro forma as adjusted basis by approximately $4.0 million, assuming that the
number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us.

Investing in our common stock involves a high degree of
risk. You should carefully consider the risks and uncertainties described below together with all of the other information contained in this prospectus, including our financial statements and the related notes appearing at the end of this
prospectus, before deciding to invest in our common stock. If any of the following risks actually occur, our business, prospects, operating results and financial condition could suffer materially. In such event, the trading price of our common stock
could decline and you might lose all or part of your investment.

Risks Related to Our Financial Position and Need For Additional Capital

We have incurred significant losses since our inception. We expect to incur losses over the next several years and may never achieve
or maintain profitability.

Since
inception, we have incurred significant operating losses. Our net loss was $12.8 million for the year ended December 31, 2011, $19.7 million for the year ended December 31, 2012 and $13.0 million for the nine months ended
September 30, 2013. As of September 30, 2013, we had an accumulated deficit of $52.5 million. To date, we have financed our operations primarily through private placements of our preferred stock and convertible bridge notes, venture debt
borrowings and, to a lesser extent, from a collaboration. All of our revenue to date has been collaboration revenue, which we first began to generate in 2013. We have devoted substantially all of our financial resources and efforts to research and
development, including preclinical studies and, beginning in 2012, clinical trials. We are still in the early stages of development of our product candidates, and we have not completed development of any drugs. We expect to continue to incur
significant expenses and operating losses over the next several years. Our net losses may fluctuate significantly from quarter to quarter and year to year.

We anticipate that our expenses will increase substantially as compared to prior periods in connection with conducting our planned pivotal
Phase 3 clinical program, consisting of two Phase 3 clinical trials evaluating the safety and efficacy of EBI-005, our most advanced product candidate, for the treatment of moderate to severe dry eye disease and a separate clinical trial evaluating
the safety of treatment with EBI-005 for one year, and seeking marketing approval for EBI-005 for this indication in the United States and, whether alone or in collaboration with third parties, in the European Union and other jurisdictions. We have
begun screening patients for our first Phase 3 trial and expect to begin randomizing and treating patients in this trial by early February 2014.

Our expenses will also increase if and as we:



pursue the development of EBI-005 for the treatment of allergic conjunctivitis or additional indications or for use in other patient populations or, if
it is approved, seek to broaden the label for EBI-005;



continue the research and development of our other product candidates;



seek to discover and develop additional product candidates;



in-license or acquire the rights to other products, product candidates or technologies for the treatment of ophthalmic diseases;

expand our operational, financial and management systems and personnel, including personnel to support our clinical development, manufacturing and
planned future commercialization efforts and our operations as a public company; and

Because of the numerous risks
and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve profitability. Our expenses will increase if:



we are required by the United States Food and Drug Administration, or FDA, or the European Medicines Agency, or EMA, to perform studies in addition to
those currently expected;



if there are any delays in receipt of regulatory clearance to begin our planned pivotal Phase 3 clinical program; or



if there are any delays in enrollment of patients in or completing our clinical trials or the development of EBI-005 or any other product candidates
that we may develop.

Our
ability to become and remain profitable depends on our ability to generate revenue. We do not expect to generate significant revenue unless and until we obtain marketing approval for, and commercialize, EBI-005, which we do not expect will occur
before 2017, if ever. This will require us to be successful in a range of challenging activities, including:



initiating and obtaining favorable results from our planned pivotal Phase 3 clinical program for EBI-005 for the treatment of moderate to severe dry
eye disease;



subject to obtaining favorable results from our planned pivotal Phase 3 clinical program for EBI-005, applying for and obtaining marketing approval for
EBI-005;



establishing sales, marketing and distribution capabilities, either ourselves or through collaboration or other arrangements with third parties, to
effectively market and sell EBI-005 in the United States;



establishing collaboration, distribution or other marketing arrangements with third parties to commercialize EBI-005 in markets outside the United
States;

Even if we do achieve profitability, we may not be able to
sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would depress the value of our company and could impair our ability to raise capital, expand our business, maintain our research and
development efforts, diversify our product offerings or even continue our operations. A decline in the value of our company could also cause you to lose all or part of your investment.

We will need substantial additional funding. If we are unable to raise capital when needed, we could be
forced to delay, reduce or eliminate our product development programs or commercialization efforts.

We expect to devote substantial financial resources to our ongoing and planned activities, particularly preparing for, initiating and
completing our planned pivotal Phase 3 clinical program evaluating EBI-005 for the treatment of moderate to severe dry eye disease and, if successful, seeking marketing approval for EBI-005. We expect to
devote additional financial resources to the clinical development of EBI-005 as we initiate and conduct additional clinical trials of EBI-005 for the treatment of
allergic conjunctivitis or other diseases and to functions associated with operating as a public company. We also expect to devote additional financial resources to conducting research and development, if we determine to proceed into clinical
development, initiating clinical trials of, and seeking regulatory approval for, our other product candidates. In addition, if we obtain regulatory approval for any of our product candidates, we would need to devote substantial financial resources
to

commercialization efforts, including product manufacturing, marketing, sales and distribution. Accordingly, we will need to obtain substantial additional funding in connection with our continuing
operations. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or any future commercialization efforts.

Our future capital requirements will depend on many factors,
including:



the progress, costs and outcome of our planned pivotal Phase 3 clinical program for EBI-005 and of any clinical activities for regulatory review of
EBI-005 outside of the United States;



the costs and timing of process development and manufacturing scale up and validation activities associated with EBI-005;



the costs, timing and outcome of regulatory review of EBI-005 in the United States, the European Union and in other jurisdictions;



the costs and timing of commercialization activities for EBI-005 if we receive, or expect to receive, marketing approval, including the costs and
timing of establishing product sales, marketing, distribution and outsourced manufacturing capabilities;



subject to receipt of marketing approval, the amount of revenue received from commercial sales of EBI-005;



the progress, costs and outcome of developing EBI-005 for the treatment of additional indications or for use in other patient populations, including
our planned Phase 2 clinical trial to assess the potential therapeutic benefit of EBI-005 for the treatment of allergic conjunctivitis in patients who do not respond adequately to antihistamines and mast cell stabilizers;

the scope, progress, results and costs of preclinical development, laboratory testing and, if we determine to proceed into clinical development,
clinical trials of our other product candidates;



the success of our collaboration with ThromboGenics N.V., or ThromboGenics;



the costs and timing of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending
any intellectual property-related claims; and



the extent to which we in-license or acquire rights to other products, product candidates or technologies for the treatment of ophthalmic diseases.

As of September 30, 2013,
we had cash and cash equivalents of $3.9 million. We believe that the net proceeds from this offering, together with our cash and cash equivalents as of September 30, 2013 and the $9.0 million in cash proceeds from our series B preferred
stock financing that we completed in December 2013, will enable us to fund our operating expenses, debt service obligations and capital expenditure requirements into the second half of 2016, without giving effect to any potential milestone payments
we may receive under our existing collaboration and license agreement with ThromboGenics. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect.

We estimate that we will incur external research and
development expenses of approximately $36 million to complete our planned pivotal Phase 3 clinical program evaluating EBI-005 and to submit a Biologics License Application, or BLA, to the FDA seeking approval of EBI-005 for the treatment of dry eye
disease in the United States in the second half of 2016. We estimate that we will incur additional external research and development expenses of approximately $3 million to complete our planned Phase 2 clinical trial evaluating the use of
EBI-005 in patients with allergic conjunctivitis. The remaining net proceeds of this offering will be used to fund our internal research and development expenses for EBI-005, internal and external research and development expenses for our
preclinical and research and discovery programs and for working capital and other general

corporate purposes during the period from the completion of this offering until we file our BLA for EBI-005 for the treatment of dry eye disease. At this time, we cannot reasonably estimate the
remaining costs necessary to commercialize EBI-005 for the treatment of dry eye disease, including commercial manufacturing of EBI-005, or the nature, timing or costs of the efforts necessary to complete the development of any other product
candidate.

Identifying potential product
candidates and conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain regulatory approval and
achieve product sales. Our commercial revenues, if any, will be derived from sales of EBI-005 or any other products that we successfully develop, none of which we expect to be commercially available for several years, if at all. In addition, if
approved, EBI-005 or any other product candidate that we develop or any product that we in-license may not achieve commercial success. Accordingly, we will need to obtain substantial additional financing to achieve our business objectives. Adequate
additional financing may not be available to us on acceptable terms, or at all. In addition, we may seek additional capital due to favorable market conditions or strategic considerations, even if we believe we have sufficient funds for our current
or future operating plans.

Raising
additional capital may cause dilution to our stockholders, including purchasers of our common stock in this offering, restrict our operations or require us to relinquish rights to our technologies or product candidates.

Until such time, if ever, as we can generate substantial
product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, government or other third-party funding, collaborations, strategic alliances, licensing arrangements and marketing and distribution
arrangements. We do not have any committed external source of funds other than funding under our existing collaboration and license agreement with ThromboGenics in the form of research funding. Under this collaboration, we also may receive potential
milestone payments upon the achievement of specified development, regulatory and other milestones and royalties with respect to future sales of collaboration products by ThromboGenics. ThromboGenics may terminate our existing collaboration for
convenience on short notice. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other
preferences that adversely affect your rights as a common stockholder. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as
incurring additional debt, making capital expenditures or declaring dividends. Our pledge of specified assets as collateral to secure our obligations under our loan and security agreement with our venture debt lender, Silicon Valley Bank, may limit
our ability to obtain additional debt financing.

If we raise additional funds through government or other third-party funding, collaborations, strategic alliances, licensing arrangements
or marketing and distribution arrangements, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us. If we are unable
to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market products or product
candidates that we would otherwise prefer to develop and market ourselves.

Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future viability.

We are an early-stage company. We were incorporated and
commenced active operations in early 2008, and our operations to date have been limited to organizing and staffing our company, acquiring rights to intellectual property, business planning, raising capital, developing our technology, identifying
potential product candidates, undertaking preclinical studies and, beginning in 2012, conducting clinical trials of EBI-005. All of our product candidates, other than EBI-005, are still in preclinical development. We have not yet demonstrated our
ability to successfully complete a pivotal Phase 3 clinical trial, obtain marketing approvals, manufacture at commercial

scale, or arrange for a third party to do so on our behalf, or conduct sales, marketing and distribution activities necessary for successful product commercialization. Consequently, any
predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history.

In addition, as a new business, we may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown
factors. We will need to transition at some point from a company with a research and development focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

We expect our financial condition and operating results to
continue to fluctuate significantly from quarter-to-quarter and year-to-year due to a variety of factors, many of which are beyond our control. Accordingly, you should not rely upon the results of any quarterly or annual periods as indications of
future operating performance.

Risks Related to the Discovery
and Development of Our Product Candidates

We depend heavily on the success of EBI-005, our most advanced product candidate, which we are developing for the treatment of
moderate to severe dry eye disease. If we are unable to successfully complete our planned pivotal Phase 3 clinical program and obtain marketing approvals for EBI-005, or experience significant delays in doing so, or if after obtaining marketing
approvals, we fail to commercialize EBI-005, our business will be materially harmed.

We have invested a significant portion of our efforts and financial resources in the development of EBI-005 for the treatment of patients with moderate to severe dry eye disease and for other
disease indications. There remains a significant risk that we will fail to successfully develop EBI-005. In 2013, we completed a Phase 1b/2a clinical trial to evaluate the safety, tolerability and biological activity of EBI-005 in patients with
moderate to severe dry eye disease. Our planned pivotal Phase 3 clinical program will consist of two Phase 3 clinical trials evaluating EBI-005 for the treatment of moderate to severe dry eye disease and a separate clinical trial evaluating the
safety of treatment with EBI-005 for one year. We have begun screening patients for our first Phase 3 trial and expect to begin randomizing and treating patients in this trial by early February 2014. We do not expect to have initial, top-line data
from our first Phase 3 trial available until early in 2015. The timing of the availability of such top-line data and the completion of our planned pivotal Phase 3 clinical program is dependent, in part, on our ability to locate and enroll a
sufficient number of eligible patients in our planned pivotal Phase 3 clinical program on a timely basis. Even if the results of both of our Phase 3 clinical trials evaluating EBI-005 for the treatment of moderate to severe dry eye disease and our
separate safety trial are favorable, we do not plan to submit a BLA to the FDA seeking approval of EBI-005 for the treatment of dry eye disease in the United States before the second half of 2016. We cannot accurately predict when or if EBI-005 will
prove effective or safe in humans or whether it will receive marketing approval. Our ability to generate product revenues, which we do not expect will occur before 2017, if ever, will depend heavily on our obtaining marketing approval for and
commercializing EBI-005.

The success
of EBI-005 will depend on several factors, including the following:

Successful development of EBI-005 for additional indications,
if any, or for use in broader patient populations and our ability, if it is approved, to broaden the label for EBI-005 will depend on similar factors. If we do not achieve one or more of these factors in a timely manner or at all, we could
experience significant delays or an inability to successfully commercialize EBI-005, which would materially harm our business.

If clinical trials of EBI-005 or any other product candidate that we develop fail to demonstrate safety and efficacy to the
satisfaction of the FDA, the EMA or other regulatory authorities or do not otherwise produce favorable results, we may incur additional costs or experience delays in completing, or ultimately be delayed or unable to complete, the development and
commercialization of EBI-005 or any other product candidate.

Before obtaining marketing approval from regulatory authorities for the sale of any product candidate, including EBI-005, we must complete preclinical development and then conduct extensive clinical
trials to demonstrate the safety and efficacy of our product candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and is uncertain as to outcome. A failure of one or
more clinical trials can occur at any stage of testing. The outcome of preclinical testing and early clinical trials may not be predictive of the success of later clinical trials, and interim results of a clinical trial do not necessarily
predict final results. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and
clinical trials have nonetheless failed to obtain marketing approval of their products.

We will be required to demonstrate the safety of treatment with EBI-005 for one year in a separate safety trial in order to support marketing approval of EBI-005 for the treatment of dry eye disease in
the United States. To meet this requirement, we plan to conduct a safety trial with no fewer than 100 patients who will be treated with EBI-005 for one year. We cannot predict the results of this safety trial because we have no clinical data on the
safety of EBI-005 when administered for a period longer than six weeks and no clinical safety data on the effects of EBI-005 when formulated with the vehicle we intend to use in our pivotal Phase 3 clinical program.

In general, the FDA requires two adequate and well controlled
clinical trials demonstrating effectiveness on two primary endpoints for marketing approval of a dry eye disease drug. One of these co-primary endpoints must be a sign of dry eye disease and the other must be a symptom of dry eye disease. We are not
aware of any investigational dry eye disease drug in development that has met these criteria. Regulatory authorities outside the United States, in particular in the European Union, have not issued guidance on the requirements for approval of a dry
eye drug. Our planned pivotal Phase 3 clinical program may not be sufficient to support an application for marketing approval outside the United States.

Our Phase 1b/2a trial evaluated EBI-005 for the treatment of moderate to severe dry eye disease. In our Phase 1b/2a trial, neither of the
doses of EBI-005 tested achieved statistically significant superiority compared to vehicle control based on any primary or secondary efficacy endpoints, including those we intend to use for our planned Phase 3 clinical trials.

Retrospective subgroup analyses that we performed on the
results of our Phase 1b/2a clinical trial may not be predictive of the results of our planned pivotal Phase 3 clinical program. We have based many elements of the design of the protocol for our planned Phase 3 clinical trials on retrospective
subgroup analyses, including our expected use of improvement in pain and discomfort as measured by the painful or sore eyes question of the

ocular surface disease index, or OSDI, as the co-primary endpoint measuring a patient symptom. In our Phase 1b/2a trial, we used total OSDI scores as a secondary efficacy endpoint. Although we
believe that the retrospective analyses support our protocol design for our planned Phase 3 clinical trials and our proposed mechanism of action, retrospective analyses performed after unmasking trial results can result in the introduction of bias
and are given less weight by regulatory authorities than pre-specified analyses.

We may fail to achieve success in our planned pivotal Phase 3 clinical program evaluating EBI-005 for the treatment of moderate to severe dry eye disease for a variety of potential reasons.



The efficacy endpoints in our Phase 1b/2a trial were measured six weeks after the first dose of EBI-005. The co-primary efficacy endpoints in our
planned pivotal Phase 3 clinical program will be measured 12 weeks after the first dose of EBI-005. We have no clinical data on EBI-005 in any clinical trial longer than six weeks.



We have made changes to the vehicle we use to formulate EBI-005 for topical, ophthalmic delivery in our planned Phase 3 clinical trials from the
vehicle used in our Phase 1b/2a trial. The most significant change to the vehicle is the removal of carboxymethyl cellulose, or CMC. CMC is a common ingredient in artificial tears. We have no clinical data on our new formulation. In addition, if the
new formulation is not comfortable to patients, patients may discontinue their participation in our planned Phase 3 clinical trials. Such discontinuations would harm our ability to complete the trial on a timely basis.



We plan to prohibit the use of rescue artificial tears by patients in our planned Phase 3 clinical trials. If the prohibition on the use of artificial
tears causes discomfort to patients and results in patients discontinuing their participation in our Phase 3 clinical trials, such discontinuations would harm our ability to complete our Phase 3 clinical trials on a timely basis.



We plan to change the eligibility criteria in our Phase 3 clinical trials from the criteria we used in our Phase 1b/2a trial with regard to patient
scores on the OSDI. We cannot predict the impact these changes will have on the rate at which patients will be enrolled or randomized in our Phase 3 clinical trials. If these changes slow the rate at which patients are enrolled or randomized
compared to the rate we anticipate, the availability of top-line clinical data from our first Phase 3 clinical trial and our completion of our planned pivotal Phase 3 clinical program will be delayed.



We plan to conduct our Phase 3 clinical trials at many clinical centers that were not included in our Phase 1b/2a trial. The introduction of new
centers, and the resulting involvement of new treating physicians, can introduce additional variability into the conduct of the trials in accordance with their protocols and may result in greater variability of patient outcomes, which could
adversely affect our ability to detect statistically significant differences between patients treated with EBI-005 and vehicle control.

If, in our first Phase 3 clinical trial, we do not demonstrate a statistically significant improvement from baseline in the EBI-005
treatment group on a pre-specified co-primary endpoint, but we do demonstrate a statistically significant improvement from baseline in the EBI-005 treatment group on one of our secondary endpoints, we may decide to substitute that secondary endpoint
for the co-primary endpoint in our second Phase 3 clinical trial prior to initiation of our second Phase 3 clinical trial. Whether this substitution and combination of results would be an acceptable means of meeting the FDAs requirement that
we duplicate in two adequate and well controlled clinical trials a statistically significant improvement on a clinically relevant sign and symptom would be a review issue at the time of our application for marketing approval. If the FDA does
not find this to be an acceptable means of meeting the requirements for marketing approval, we will not receive marketing approval for EBI-005, and we will have to conduct another Phase 3 clinical trial if we wish to seek marketing approval for
EBI-005 in the future. Additionally, if we initiate our second Phase 3 clinical trial of EBI-005 before we have completed our first Phase 3 clinical trial, the option to substitute a secondary endpoint from the first Phase 3 clinical trial for
a co-primary endpoint in the second Phase 3 clinical trial would not be available to us.

The protocols for our planned pivotal Phase 3 clinical program and other supporting information are subject to review by the FDA and regulatory authorities outside the United States. The FDA or other
regulatory

authorities may request additional information, require us to conduct additional non-clinical trials or require us to modify our planned pivotal Phase 3 clinical program, including its endpoints
or patient enrollment criteria, to receive clearance to initiate such program or to continue such program once initiated. If our Phase 3 program is placed on clinical hold by the FDA, we may be significantly delayed and incur significantly greater
expense in our proposed development program. For example, our Phase 1b/2a trial of EBI-005 was placed on clinical hold between September 6, 2012 and October 29, 2012 until we provided particular manufacturing stability information
regarding the drug product lots intended to be used in our clinical studies. The FDA is not obligated to comment on our protocols within any specified time period or at all or to affirmatively clear or approve our planned pivotal Phase 3 clinical
program. We have submitted the protocol for our first planned pivotal Phase 3 clinical trial to the FDA. We intend to submit the protocols for our second planned pivotal Phase 3 clinical trial and our separate safety study of EBI-005 to the FDA. We
are initiating our planned pivotal Phase 3 clinical program in the United States without waiting for comments, clearance or approval from the FDA. We have not received guidance from the EMA or other regulatory authorities outside the United States
regarding the design of our planned pivotal Phase 3 clinical program. We are currently seeking scientific advice from the EMA to confirm the requirements for Phase 3 clinical trials in the European Union. We have submitted to the EMA the protocol
for a Phase 3 clinical trial to be conducted as part of our planned pivotal Phase 3 clinical program. The EMA has requested additional information from us and has scheduled a discussion meeting with us in early February 2014. We may not
receive clearance from the EMA or other regulatory authorities to initiate our planned pivotal Phase 3 clinical program on a timely basis, if at all.

If we experience any of a number of possible unforeseen events in connection with our clinical trials, potential marketing approval
or commercialization of our product candidates could be delayed or prevented.

We may experience numerous unforeseen events during, or as a result of, clinical trials that could delay or prevent our ability to receive marketing approval or commercialize EBI-005 or any other product
candidates that we may develop, including:



clinical trials of our product candidates may produce negative or inconclusive results, and we may decide, or regulators may require us, to conduct
additional clinical trials or abandon product development programs;



the number of patients required for clinical trials of our product candidates may be larger than we anticipate, enrollment in these clinical trials may
be slower than we anticipate or participants may drop out of these clinical trials at a higher rate than we anticipate;



our third-party contractors may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all;



the change in the vialing of EBI-005 to blow-fill-seal vials for our planned pivotal Phase 3 clinical program in place of single-use, screw-top vials
as used in our Phase 1b/2a trial may result in unforeseen difficulties or delays;



regulators or institutional review boards may not authorize us or our investigators to commence a clinical trial or conduct a clinical trial at a
prospective trial site;



we may experience delays in reaching, or fail to reach, agreement on acceptable clinical trial contracts or clinical trial protocols with prospective
trial sites;



we may decide, or regulators or institutional review boards may require us, to suspend or terminate clinical research for various reasons, including
noncompliance with regulatory requirements or a finding that the participants are being exposed to unacceptable health risks;



the cost of clinical trials of our product candidates may be greater than we anticipate;



the supply or quality of our product candidates or other materials necessary to conduct clinical trials of our product candidates may be insufficient
or inadequate; and

our product candidates may have undesirable side effects or other unexpected characteristics, causing us or our investigators, regulators or
institutional review boards to suspend or terminate the trials.

If we are required to conduct additional clinical trials or other testing of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials of
our product candidates or other testing, if the results of these trials or tests are not favorable or are only modestly favorable or if there are safety concerns, we may:



be delayed in obtaining marketing approval for our product candidates;



not obtain marketing approval at all;



obtain approval for indications or patient populations that are not as broad as intended or desired;



obtain approval with labeling that includes significant use or distribution restrictions or safety warnings;



be subject to additional post-marketing testing requirements; or



have the product removed from the market after obtaining marketing approval.

Our product development costs will also increase if we experience delays in testing or marketing approvals. We
do not know whether any of our preclinical studies or clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all. Significant preclinical or clinical trial delays also could shorten any periods
during which we may have the exclusive right to commercialize our product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize our product candidates.

If we experience delays or difficulties in the
enrollment of patients in clinical trials, our receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate or continue clinical trials for EBI-005 or our other product candidates that we may develop if we are
unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required by the FDA or similar regulatory authorities outside the United States. In addition, some of our competitors have ongoing clinical trials
for product candidates that treat the same indications as EBI-005, and patients who would otherwise be eligible for our clinical trials may instead enroll in clinical trials of our competitors product candidates.

Patient enrollment is affected by other factors including:



the severity of the disease under investigation;



the eligibility criteria for the study in question;



the perceived risks and benefits of the product candidate under study;



the efforts to facilitate timely enrollment in clinical trials;



the patient referral practices of physicians;



the ability to monitor patients adequately during and after treatment; and



the proximity and availability of clinical trial sites for prospective patients.

Our inability to enroll a sufficient number of patients for
our clinical trials would result in significant delays, could require us to abandon one or more clinical trials altogether and could delay or prevent our receipt of necessary regulatory approvals. Enrollment delays in our clinical trials may result
in increased development costs for our product candidates, which would cause the value of our company to decline and limit our ability to obtain additional financing.

If serious adverse or unacceptable side effects are identified during the development
of EBI-005 or any other product candidates that we may develop, we may need to abandon or limit our development of EBI-005 or such other product candidates.

If EBI-005 or any of our other product candidates are
associated with serious adverse events or undesirable side effects in clinical trials or have characteristics that are unexpected, we may need to abandon their development or limit development to more narrow uses or subpopulations in which the
serious adverse events, undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. Although EBI-005 was generally well tolerated in our Phase 1b/2a trial, we have no clinical
safety data on or patient exposure to EBI-005 for longer than six weeks. We have no clinical safety data on patient exposure to EBI-005 formulated with the vehicle we intend to use in our Phase 3 clinical trials. Many compounds that initially showed
promise in clinical or early stage testing for treating ophthalmic disease have later been found to cause side effects that prevented further development of the compound.

We may not be successful in our efforts to use our
AMP-Rx platform to build a pipeline of product candidates.

A key element of our strategy is to use our proprietary AMP-Rx platform to rationally design, engineer and generate a pipeline of novel protein therapies and progress these therapies through clinical
development for the treatment of a variety of ophthalmic diseases. Our research and development efforts to date have resulted in a pipeline of additional product candidates directed at the treatment of ophthalmic diseases. Other than EBI-005, our
product candidates all are in early preclinical research and have not been tested in humans. These and any other potential product candidates that we identify may not be suitable for continued preclinical or clinical development, including as a
result of being shown to have harmful side effects or other characteristics that indicate that they are unlikely to be products that will receive marketing approval and achieve market acceptance. If we do not successfully develop and commercialize
our product candidates that we develop based upon our technological approach, we will not be able to obtain product revenues in future periods.

We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product
candidates or indications that may be more profitable or for which there is a greater likelihood of success.

Because we have limited financial and managerial resources, we focus on research programs and product candidates that we identify for
specific indications. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail
to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs and product candidates for specific indications may not yield any commercially viable products. If
we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which
it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

Risks Related to the Commercialization of Our Product Candidates

Even if EBI-005 or any other product candidate that we
develop receives marketing approval, it may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success and the market opportunity for EBI-005 may
be smaller than we estimate.

If EBI-005
or any other product candidate that we develop receives marketing approval, it may nonetheless fail to gain sufficient market acceptance by physicians, patients, third-party payors and others in the medical community. Current treatments that are
used for moderate to severe dry eye disease include low cost artificial tears, Restasis and

low cost, off-label use of corticosteroids. These treatments are well established in the medical community, and doctors may continue to rely on these treatments rather than EBI-005, if and when
it is approved for marketing by the FDA. In addition, it is possible that the FDA may approve generic versions of Restasis in the foreseeable future. The patent on Restasis expires on May 17, 2014. If generic versions of Restasis are approved
for marketing by the FDA, they would likely be offered at a substantially lower price than EBI-005. As a result, healthcare professionals and third-party payors may choose to rely on such products rather than EBI-005. If EBI-005 does not achieve an
adequate level of acceptance, we may not generate significant product revenues and we may not become profitable.

The degree of market acceptance of EBI-005 or any other product candidate that we may develop, if approved for commercial sale, will
depend on a number of factors, including:



the efficacy and potential advantages compared to alternative treatments, including the existing standard of care;



our ability to offer our products for sale at competitive prices, particularly in light of the lower cost of alternative treatments;



the convenience and ease of administration compared to alternative treatments;



the willingness of the target patient population to try new therapies and of physicians to prescribe these therapies;



the strength of our marketing and distribution support;



timing of market introduction of competitive products;



the availability of third-party coverage and adequate reimbursement, particularly by Medicare in light of the prevalence of dry eye disease in persons
over age 55;



the prevalence and severity of any side effects; and



any restrictions on the use of our products together with other medications.

Our assessment of the potential market opportunity for EBI-005 is based on industry and market data that we
obtained from industry publications and research, surveys and studies conducted by third parties. Industry publications and third-party research, surveys and studies generally indicate that their information has been obtained from sources believed
to be reliable, although they do not guarantee the accuracy or completeness of such information. If the actual market for EBI-005 is smaller than we expect, our product revenue may be limited and it may be more difficult for us to achieve or
maintain profitability.

If we are unable to
establish sales, marketing and distribution capabilities, we may not be successful in commercializing EBI-005 or any other product candidates that we may develop if and when they are approved.

We do not have a sales or marketing infrastructure and have
no experience in the sale, marketing or distribution of therapeutic products. To achieve commercial success for any product for which we have obtained marketing approval, we will need to establish sales, marketing and distribution capabilities,
either ourselves or through collaborations or other arrangements with third parties.

In the future, we plan to build a focused sales and marketing infrastructure to market or co-promote EBI-005 and possibly other product candidates that we develop
in the United States, if and when they are approved. There are risks involved with establishing our own sales, marketing and distribution capabilities. For example, recruiting and training a sales force is expensive and time consuming and could
delay any product launch. If the commercial launch of EBI-005 or any other product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely or
unnecessarily incurred these commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel.

the inability of sales personnel to obtain access to physicians or persuade adequate numbers of physicians to prescribe our products;



the lack of complementary products to be offered by sales personnel, which may put us at a competitive disadvantage relative to companies with more
extensive product lines; and



unforeseen costs and expenses associated with creating an independent sales and marketing organization.

We expect to enter into arrangements with third parties to
perform sales, marketing and distribution services in markets outside the United States. We may also enter into arrangements with third parties to perform these services in the United States if we do not establish our own sales, marketing and
distribution capabilities in the United States or if we determine that such third-party arrangements are otherwise beneficial. Our product revenues and our profitability, if any, under any such third-party sales, marketing or distribution
arrangements are likely to be lower than if we were to market, sell and distribute EBI-005 or any other product candidates that we may develop ourselves. In addition, we may not be successful in entering into arrangements with third parties to sell,
market and distribute EBI-005 or any other product candidates or may be unable to do so on terms that are favorable to us. We likely will have little control over such third parties, and any of them may fail to devote the necessary resources and
attention to sell and market EBI-005 or our other product candidates effectively. If we do not establish sales, marketing and distribution capabilities successfully, either on our own or in collaboration with third parties, we will not be successful
in commercializing EBI-005 or any other product candidates that we may develop.

We face substantial competition, which may result in others discovering, developing or commercializing products before or more successfully than we do.

The development and commercialization of new drug products
is highly competitive. We face competition with respect to EBI-005 and our other current product candidates, and will face competition with respect to any product candidates that we may seek to develop or commercialize in the future, from major
pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide. There are a number of large pharmaceutical and biotechnology companies that currently market and sell products or are pursuing the development of
products for the treatment of the disease indications for which we are developing our product candidates. Potential competitors also include academic institutions, government agencies and other public and private research organizations that conduct
research, seek patent protection and establish collaborative arrangements for research, development, manufacturing and commercialization.

The current standard of care for dry eye disease includes artificial tears and topical anti-inflammatory and immune-modulating drugs. The
anti-inflammatory and immune-modulating drug market for the treatment of moderate to severe dry eye disease consists primarily of Restasis, which is approved for use in the United States, and off-label use of corticosteriods. Some patients with
moderate to severe dry eye disease are effectively treated by the current standard of care therapies, some of which are available in generic form or offered at relatively low prices. There are also a number of products and therapies in preclinical
research and clinical development by third parties to treat dry eye disease. Some of these competitive products and therapies are based on scientific approaches that are the same as or similar to our approach, and others are based on entirely
different approaches. These companies include pharmaceutical companies, biotechnology companies, and specialty pharmaceutical and generic drug companies of various sizes, such as Shire Plc (lifitegrast), Acucela Inc., in collaboration with Otsuka
Pharmaceutical Co., Ltd. (rebamipide), Mimetogen Pharmaceuticals Inc., in collaboration with Bausch + Lomb Corporation (MIM-D3), OphthaliX Inc. (CF101), Rigel Pharmaceuticals, Inc. (R9348) and Allergan, Inc. (AGN-195263). See
BusinessCompetition for additional information regarding our competitors.

In 2013, the peer-reviewed journal JAMA Ophthalmology published the results of an
exploratory clinical trial in 75 patients conducted by one of our scientific co-founders, Dr. Reza Dana, at the Massachusetts Eye and Ear Infirmary using anakinra to treat patients with moderate to severe dry eye disease. Interleukin-1, or
IL-1, is the therapeutic target of both anakinra and EBI-005, and the mechanisms of action of anakinra and EBI-005 are very similar. For this proof-of-concept study, the investigators compounded, or reformulated, anakinra in eye drops at two
different concentrations for topical administration. The investigators reported positive results from this trial. We believe that the investigators continue to treat dry eye patients using reformulated anakinra. We would face competition
with respect to EBI-005 if reformulated anakinra was available commercially through compounding pharmacies or if a third party successfully completed pivotal clinical trials of, and received marketing approval for, reformulated anakinra for the
treatment of dry eye disease.

Our commercial
opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than EBI-005 or other product
candidates that we may develop. Our competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before
we are able to enter the market.

In addition, our
ability to compete may be affected in many cases by insurers or other third-party payors, particularly Medicare, seeking to encourage the use of generic products. Generic products are currently being used for the indications that we are pursuing,
and additional products are expected to become available on a generic basis over the coming years. For example, the FDAs Office of Generic Drugs recently released guidance for the development of generic versions of Restasis. If EBI-005 or any
other product candidate that we may develop achieves marketing approval, we expect that it will be priced at a significant premium over competitive generic products.

Many of the companies against which we are competing or
against which we may compete in the future have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing
approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller and other early stage companies may
also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These third parties compete with us in recruiting and retaining qualified scientific and management personnel,
establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

Even if we are able to commercialize EBI-005 or any
other product candidate that we may develop, the products may become subject to unfavorable pricing regulations, third-party coverage or reimbursement practices or healthcare reform initiatives, which could harm our business.

Our ability to commercialize EBI-005 or any other product
candidates that we may develop successfully will depend, in part, on the extent to which coverage and adequate reimbursement for these products and related treatments will be available from government healthcare programs, private health insurers,
managed care plans and other organizations. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. A primary
trend in the U.S. healthcare industry and elsewhere is cost containment. Government authorities and third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. Increasingly,
third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products. Coverage and reimbursement may not be available for EBI-005 or any other
product that we commercialize and, even if they are available, the level of reimbursement may not be satisfactory.

Inadequate reimbursement may adversely affect the demand for, or the price of, any product candidate for which we obtain marketing
approval. Obtaining and maintaining adequate reimbursement for our products may

be difficult. We may be required to conduct expensive pharmacoeconomic studies to justify coverage and reimbursement or the level of reimbursement relative to other therapies. If coverage and
adequate reimbursement are not available or reimbursement is available only to limited levels, we may not be able to successfully commercialize EBI-005 or any other product candidate for which we obtain
marketing approval.

There may be significant
delays in obtaining coverage and reimbursement for newly approved drugs, and coverage may be more limited than the indications for which the drug is approved by the FDA or similar regulatory authorities outside the United States. Moreover,
eligibility for coverage and reimbursement does not imply that a drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution expenses. Interim reimbursement levels for
new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels
already set for lower cost drugs and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future
relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own
reimbursement policies. Our inability to promptly obtain coverage and adequate reimbursement rates from both government-funded and private payors for any approved products that we develop would compromise our ability to generate revenues and become
profitable.

The regulations that govern marketing
approvals, pricing, coverage and reimbursement for new drug products vary widely from country to country. Current and future legislation may significantly change the approval requirements in ways that could involve additional costs and cause delays
in obtaining approvals. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In some foreign markets,
prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain marketing approval for a product in a particular country, but then be subject to price
regulations that delay our commercial launch of the product, possibly for lengthy time periods, and negatively impact the revenues we are able to generate from the sale of the product in that country. To obtain reimbursement or pricing approval in
some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. Adverse pricing limitations may hinder our ability to recoup our investment in one or more
product candidates, even if our product candidates obtain marketing approval.

There can be no assurance that our product candidates or any products that we may in-license, if they are approved for sale in the United States or in other countries, will be considered medically
reasonable and necessary for a specific indication, that they will be considered cost-effective by third-party payors, that coverage and an adequate level of reimbursement will be available, or that third-party payors reimbursement policies
will not adversely affect our ability to sell our product candidates profitably.

Our strategy of obtaining rights to product candidates and approved products for the treatment of a range of ophthalmic diseases through in-licenses and acquisitions may not be successful.

We may expand our product pipeline
through opportunistically in-licensing or acquiring the rights to other products, product candidates or technologies for the treatment of ophthalmic diseases. The future growth of our business may depend in part on our ability to in-license or
acquire the rights to approved products, additional product candidates or technologies. However, we may be unable to in-license or acquire the rights to any such products, product candidates or technologies from third parties. The in-licensing and
acquisition of pharmaceutical products is a competitive area, and a number of more established companies are also pursuing strategies to license or acquire products, product candidates or technologies that we may consider attractive. These
established companies may have a competitive advantage over us due to their size, cash resources and greater clinical development and commercialization capabilities.

In addition, companies that perceive us to be a competitor may be unwilling to assign or
license rights to us. We also may be unable to in-license or acquire the rights to the relevant product, product candidate or technology on terms that would allow us to make an appropriate return on our investment. Furthermore, we may be unable to
identify suitable products, product candidates or technologies within our area of focus. If we are unable to successfully obtain rights to suitable products, product candidates or technologies, our ability to pursue this element of our strategy
could be impaired.

Product liability
lawsuits against us could cause us to incur substantial liabilities and to limit commercialization of any products that we develop.

We face an inherent risk of product liability exposure related to the use of EBI-005 and any other product candidates that we develop in
human clinical trials and will face an even greater risk if we commercially sell any products that we develop. If we cannot successfully defend ourselves against claims that our product candidates or products caused injuries, we will incur
substantial liabilities. Regardless of merit or eventual outcome, liability claims may result in:



decreased demand for any product candidates or products that we develop;



injury to our reputation and significant negative media attention;



withdrawal of clinical trial participants;



significant costs to defend the related litigation;



substantial monetary awards to trial participants or patients;



loss of revenue;



reduced time and attention of our management to pursue our business strategy; and



the inability to commercialize any products that we develop.

We currently hold $5.0 million in product liability insurance
coverage in the aggregate, with a per incident limit of $5.0 million, which may not be adequate to cover all liabilities that we may incur. We will need to increase our insurance coverage as we expand our clinical trials. We will need to further
increase our insurance coverage if we commence commercialization of EBI-005 or any other product candidate that receives marketing approval. Insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a
reasonable cost or in an amount adequate to satisfy any liability that may arise.

Risks Related to Our Dependence on Third Parties

We have entered into one collaboration and in the future may enter into collaborations with other third parties for the development
or commercialization of our product candidates, including EBI-005. If our collaborations are not successful, we may not be able to capitalize on the market potential of these product candidates.

In May 2013, we entered into a collaboration and license
agreement with ThromboGenics. Under the agreement, we and ThromboGenics are collaborating to identify protein or peptide therapeutics that directly modulate any of a specified set of targets in a novel pathway in retinal disease. This collaboration
generally prohibits us, our affiliates and any entities which become affiliates of ours as a result of an acquisition of us by a third party, from researching, developing, manufacturing or commercializing any protein or peptide therapeutic that
directly modulates one of the specified targets, except as otherwise provided in the agreement. This restriction may have the effect of preventing us from undertaking development and other efforts that may appear to be attractive to us.

We expect to utilize a variety of types of collaboration,
distribution and other marketing arrangements with third parties to commercialize EBI-005 in markets outside the United States. We also may enter into

arrangements with third parties to perform these services in the United States if we do not establish our own sales, marketing and distribution capabilities in the United States or if we
determine that such third-party arrangements are otherwise beneficial. We also may seek third-party collaborators for development and commercialization of other product candidates. Our likely collaborators for any sales, marketing, distribution,
development, licensing or broader collaboration arrangements include large and mid-size pharmaceutical companies, regional and national pharmaceutical companies and biotechnology companies. We are not currently party to any such arrangement. Our
ability to generate revenues from these arrangements will depend on our collaborators abilities and efforts to successfully perform the functions assigned to them in these arrangements.

Our existing collaboration with ThromboGenics and any future collaborations that we enter into, may pose a
number of risks, including the following:



collaborators have significant discretion in determining the amount and timing of efforts and resources that they will apply to these collaborations;



collaborators may not perform their obligations as expected;



collaborators may not pursue development and commercialization of our product candidates that receive marketing approval or may elect not to continue
or renew development or commercialization programs based on clinical trial results, changes in the collaborators strategic focus or available funding, or external factors, such as an acquisition, that divert resources or create competing
priorities;



collaborators may delay clinical trials, provide insufficient funding for a clinical trial program, stop a clinical trial or abandon a product
candidate, repeat or conduct new clinical trials or require a new formulation of a product candidate for clinical testing;



collaborators could independently develop, or develop with third parties, products that compete directly or indirectly with our products or product
candidates if the collaborators believe that competitive products are more likely to be successfully developed or can be commercialized under terms that are more economically attractive than ours;



product candidates discovered in collaboration with us may be viewed by our collaborators as competitive with their own product candidates or products,
which may cause collaborators to cease to devote resources to the commercialization of our product candidates;



a collaborator with marketing and distribution rights to one or more of our product candidates that achieve regulatory approval may not commit
sufficient resources to the marketing and distribution of such product or products;



disagreements with collaborators, including disagreements over proprietary rights, contract interpretation or the preferred course of development,
might cause delays or termination of the research, development or commercialization of product candidates, might lead to additional responsibilities for us with respect to product candidates, or might result in litigation or arbitration, any of
which would divert management attention and resources, be time-consuming and expensive;



collaborators may not properly maintain or defend our intellectual property rights or may use our proprietary information in such a way as to invite
litigation that could jeopardize or invalidate our intellectual property or proprietary information or expose us to potential litigation;



collaborators may infringe the intellectual property rights of third parties, which may expose us to litigation and potential liability; and



collaborations may be terminated for the convenience of the collaborator and, if terminated, we could be required to raise additional capital to pursue
further development or commercialization of the applicable product candidates.

Collaboration agreements may not lead to development or commercialization of product candidates in the most efficient manner, or at all. If our existing collaboration and license agreement with
ThromboGenics, and

any future collaborations that we enter into, do not result in the successful development and commercialization of products or if one of our collaborators terminates its agreement with us, we may
not receive any future research funding or milestone or royalty payments under the collaboration. If we do not receive the funding we expect under these agreements, our development of our product candidates could be delayed and we may need
additional resources to develop our product candidates. All of the risks relating to product development, regulatory approval and commercialization described in this prospectus also apply to the activities of our collaborators.

Additionally, subject to its contractual obligations to us,
if a collaborator of ours were to be involved in a business combination, it might deemphasize or terminate the development or commercialization of any product candidate licensed to it by us. If one of our collaborators terminates its agreement with
us, we may find it more difficult to attract new collaborators and our perception in the business and financial communities could be harmed.

If we are not able to establish additional collaborations, we may have to alter our development and commercialization plans and our
business could be adversely affected.

For some of our product candidates, we may decide to collaborate with pharmaceutical and biotechnology companies for the development and
potential commercialization of therapeutic products. We face significant competition in seeking appropriate collaborators. Whether we reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the
collaborators resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborators evaluation of a number of factors. Those factors may include the design or results of clinical trials, the
likelihood of approval by the FDA or similar regulatory authorities outside the United States, the potential market for the subject product candidate, the costs and complexities of manufacturing and delivering such product candidate to patients, the
potential of competing products, the existence of uncertainty with respect to our ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge, and industry and market conditions
generally. The collaborator may also consider alternative product candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us for our
product candidate. We may also be restricted under future license agreements from entering into agreements on certain terms with potential collaborators. Collaborations are complex and time-consuming to negotiate and document. In addition, there
have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators.

If we are unable to reach agreements with suitable
collaborators on a timely basis, on acceptable terms, or at all, we may have to curtail the development of a product candidate, reduce or delay its development program or one or more of our other development programs, delay its potential
commercialization or reduce the scope of any sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to fund and undertake development or commercialization
activities on our own, we may need to obtain additional expertise and additional capital, which may not be available to us on acceptable terms or at all. If we fail to enter into collaborations and do not have sufficient funds or expertise to
undertake the necessary development and commercialization activities, we may not be able to further develop our product candidates or bring them to market or continue to develop our product platform.

We rely, and expect to continue to rely, on third
parties to conduct our clinical trials, and those third parties may not perform satisfactorily, including failing to meet deadlines for the completion of such trials.

We have relied on third parties, such as contract research
organizations, or CROs, to conduct our completed Phase 1 and Phase 1b/2a trials of EBI-005 and do not plan to independently conduct clinical trials of EBI-005 or our other product candidates, including our planned Phase 3 clinical trials of EBI-005.
We expect to continue to rely on third parties, such as CROs, clinical data management organizations, medical institutions and clinical investigators, to conduct our clinical trials. These agreements might terminate for a variety of reasons,
including

a failure to perform by the third parties. If we need to enter into alternative arrangements, that would delay our product development activities.

Our reliance on these third parties for research and
development activities will reduce our control over these activities but will not relieve us of our responsibilities. For example, we will remain responsible for ensuring that each of our clinical trials is conducted in accordance with the general
investigational plan and protocols for the trial. Moreover, the FDA requires us to comply with standards, commonly referred to as good clinical practices for conducting, recording and reporting the results of clinical trials to assure that data and
reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. We also are required to register ongoing clinical trials and post the results of completed clinical trials on a
government-sponsored database, ClinicalTrials.gov, within specified timeframes. Failure to do so can result in fines, adverse publicity and civil and criminal sanctions.

Furthermore, these third parties may also have relationships
with other entities, some of which may be our competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or conduct our clinical trials in accordance with regulatory requirements or our stated
protocols, we will not be able to obtain, or may be delayed in obtaining, marketing approvals for our product candidates and will not be able to, or may be delayed in our efforts to, successfully commercialize our product candidates.

We contract with third parties for the manufacture of
EBI-005 for clinical trials and expect to continue to do so in connection with the commercialization of EBI-005 and for clinical trials and commercialization of any other product candidates that we may develop. This reliance on third parties
increases the risk that we will not have sufficient quantities of our product candidates or products or such quantities at an acceptable cost, which could delay, prevent or impair our development or commercialization efforts

We do not currently own or operate manufacturing facilities
for the production of clinical or commercial quantities of EBI-005 or any other of our product candidates. We rely, and expect to continue to rely, on third parties to manufacture clinical and commercial supplies of EBI-005, preclinical and clinical
supplies of our other product candidates that we may develop and commercial supplies of products if and when any of our product candidates receives marketing approval. Our current and anticipated future dependence upon others for the manufacture of
EBI-005 and any other product candidate or product that we develop may adversely affect our future profit margins and our ability to commercialize any products that receive marketing approval on a timely and competitive basis. In addition, any
performance failure on the part of our existing or future manufacturers could delay clinical development or marketing approval.

We currently rely exclusively on one third-party manufacturer to supply us with EBI-005 drug substance on a purchase order basis. We also
rely on another third-party manufacturer to conduct fill-finish services on a purchase order basis. We do not currently have any contractual commitments for commercial supply of bulk drug substance for EBI-005 or for fill-finish services. We also do
not currently have arrangements in place for redundant supply or a second source for bulk drug substance for EBI-005 or for fill-finish services. The prices at which we are able to obtain supplies of EBI-005 drug substance and fill-finish services
may vary substantially over time and adversely affect our financial results.

If our third-party manufacturer for EBI-005 drug substance fails to fulfill our purchase orders or should become unavailable to us for any reason, we believe that there are a limited number of potential
replacement manufacturers, and we likely would incur added costs and delays in identifying or qualifying such replacements. We could also incur additional costs and delays in identifying or qualifying a replacement manufacturer for fill-finish
services if our existing third-party manufacturer should become unavailable for any reason. We may be unable to establish any agreements with such replacement manufacturers or to do so on acceptable terms. Even if we could transfer manufacturing to
a different third party, the shift would likely be expensive and time consuming, particularly since the new facility would need to comply with the necessary regulatory requirements and we would need FDA approval before using or selling any products
manufactured at that facility.

The FDA maintains strict requirements governing the manufacturing process for biologics.
When a manufacturer seeks to modify or make even seemingly minor changes to that process, the FDA may require the applicant to conduct a comparability study that evaluates the potential differences in the product resulting from the change in the
manufacturing process. The agency has issued several guidances on this point. In connection with our application for a license to market EBI-005 or other product candidates in the United States, we may be required to conduct a comparability study if
the product we intend to market is supplied by a manufacturer different from the one who supplied the product evaluated in our clinical studies. Delays in designing and completing this study to the satisfaction of the FDA could delay or preclude our
development and commercialization plans and thereby limit our revenues and growth.

EBI-005 and any other product candidates that we may develop may compete with other product candidates and products for access to a limited number of
suitable manufacturing facilities that operate under current good manufacturing practices, or cGMP, regulations;



reliance on the third party for regulatory compliance and quality assurance;



the possible breach of the manufacturing agreement by the third party;



the possible misappropriation of our proprietary information, including our trade secrets and know-how; and



the possible termination or nonrenewal of the agreement by the third party at a time that is costly or inconvenient for us.

Third-party manufacturers may
not be able to comply with cGMP regulations or similar regulatory requirements outside the United States. Our failure, or the failure of our third-party manufacturers, to comply with applicable regulations could result in sanctions being imposed on
us, including clinical holds, fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates or products, operating restrictions and criminal prosecutions, any of
which could significantly and adversely affect supplies of our products.

Risks Related to Our Intellectual Property

If we are unable to obtain and maintain patent protection for our technology and products, or if our licensors are unable to obtain and maintain patent protection for the technology or products that
we license from them, or if the scope of the patent protection obtained is not sufficiently broad, our competitors could develop and commercialize technology and products similar or identical to ours, and our ability to successfully commercialize
our technology and products may be impaired.

Our success depends in large part on our and our licensors ability to obtain and maintain patent protection in the United States and other countries with respect to our proprietary technology and
products. We and our licensors have sought to protect our proprietary position by filing patent applications in the United States and abroad related to our novel technologies and product candidates. The patent prosecution process is expensive and
time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of our research and
development output before it is too late to obtain patent protection. Moreover, in some circumstances, we do not have the right to control the preparation, filing and prosecution of patent applications, or to maintain the patents, covering
technology that we license from third parties. Therefore, these patents and applications may not be prosecuted and enforced in a manner consistent with the best interests of our business. If such licensors fail to maintain such patents, or lose
rights to those patents, the rights we have licensed may be reduced or eliminated.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation.
As a result, the

issuance, scope, validity, enforceability and commercial value of our and our licensors patent rights are highly uncertain. Our and our licensors pending and future patent
applications may not result in patents being issued which protect our technology or products or which effectively prevent others from commercializing competitive technologies and products. In addition, the laws of foreign countries may not protect
our rights to the same extent as the laws of the United States. For example, European patent law restricts the patentability of methods of treatment of the human body more than United States law does. Publications of discoveries in the scientific
literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing, or in some cases not at all. Therefore, we cannot know with certainty
whether we or our licensors were the first to make the inventions claimed in our owned or licensed patents or pending patent applications, or that we or our licensors were the first to file for patent protection of such inventions. As a result, the
issuance, scope, validity, enforceability and commercial value of our owned or licensed patent rights are highly uncertain. Our pending and future patent applications may not result in patents being issued which protect our technology or products,
in whole or in part, or which effectively prevent others from commercializing competitive technologies and products. In particular, during prosecution of any patent application, the issuance of any patents based on the application may depend upon
our ability to generate additional preclinical or clinical data that support the patentability of our proposed claims. We may not be able to generate sufficient additional data on a timely basis, or at all. Moreover, changes in either the patent
laws or interpretation of the patent laws in the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection.

Recent patent reform legislation could increase the
uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents. On September 16, 2011, the Leahy-Smith America Invents Act, or the Leahy-Smith Act, was signed into law. The
Leahy-Smith Act includes a number of significant changes to United States patent law. These include provisions that affect the way patent applications are prosecuted and may also affect patent litigation. The United States Patent Office recently
developed new regulations and procedures to govern administration of the Leahy-Smith Act, and many of the substantive changes to patent law associated with the Leahy-Smith Act, and in particular, the first to file provisions, only became effective
on March 16, 2013. Accordingly, it is not clear what, if any, impact the Leahy-Smith Act will have on the operation of our business. However, the Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the
prosecution of our patent applications and the enforcement or defense of our issued patents.

Moreover, we may be subject to a third-party preissuance submission of prior art to the U.S. Patent and Trademark Office, or become involved in opposition, derivation, reexamination, inter partes
review, post-grant review or interference proceedings challenging our patent rights or the patent rights of others. An adverse determination in any such submission, proceeding or litigation could reduce the scope of, or invalidate, our patent
rights, allow third parties to commercialize our technology or products and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize products without infringing third-party patent rights. In
addition, if the breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

Even if our owned and licensed patent
applications issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors from competing with us or otherwise provide us with any competitive advantage. Our competitors may be able to
circumvent our owned or licensed patents by developing similar or alternative technologies or products in a non-infringing manner.

We are the exclusive licensee of patent applications owned by The Schepens Eye Research Institute, Inc., or Schepens, that cover methods
of treating diseases of the eye using an inhibitor of the inflammatory cytokine IL-1. Even if these applications issue as patents, method-of-treatment patents are more difficult to enforce than
composition-of-matter patents because of the risk of off-label sale or use of a drug for the subject method. In addition, European patent law generally makes the enforcement of patents that cover methods of treatment of the

human body difficult. In the United States, the FDA does not prohibit physicians from prescribing an approved product for uses that are not described in the products labeling. Although use
of a product directed by off-label prescriptions may infringe our method-of-treatment patents, the practice is common across medical specialties, particularly in the United States, and such infringement is difficult to detect, prevent or prosecute.
For example, anakinra is an IL-1 inhibitor that is approved for marketing in the United States and other countries for the treatment of rheumatoid arthritis and is formulated for subcutaneous administration. Anakinra can be re-formulated, or
compounded, for topical ophthalmic application. Off-label sales of anakinra or other products comprising an IL-1 inhibitor could limit our ability to generate revenue from the sale of EBI-005.

The issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, and our
owned and licensed patents may be challenged in the courts or patent offices in the United States and abroad. Such challenges may result in loss of exclusivity or freedom to operate or in patent claims being narrowed, invalidated or held
unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar or identical technology and products, or limit the duration of the patent protection of our technology and products. Given the
amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed
patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours.

We may become involved in lawsuits to protect or enforce our patents or other intellectual property, which could be expensive, time
consuming and unsuccessful.

Competitors
may infringe our issued patents or other intellectual property. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time consuming. Any claims we assert against perceived infringers
could provoke these parties to assert counterclaims against us alleging that we infringe their patents. In addition, in a patent infringement proceeding, a court may decide that a patent of ours is invalid or unenforceable, in whole or in part,
construe the patents claims narrowly or refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation proceeding could put one or
more of our patents at risk of being invalidated or interpreted narrowly. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential
information could be compromised by disclosure during this type of litigation.

Third parties may initiate legal proceedings alleging that we are infringing their intellectual property rights, the outcome of which would be uncertain and could have a material adverse effect on
the success of our business.

Our
commercial success depends upon our ability, and the ability of our collaborators, to develop, manufacture, market and sell our product candidates and use our proprietary technologies without infringing the proprietary rights of third parties. There
is considerable intellectual property litigation in the biotechnology and pharmaceutical industries. We may become party to, or threatened with, future adversarial proceedings or litigation regarding intellectual property rights with respect to our
products and technology, including interference or derivation proceedings before the U.S. Patent and Trademark Office. The risks of being involved in such litigation and proceedings may increase as our product candidates near commercialization and
as we gain the greater visibility associated with being a public company. Third parties may assert infringement claims against us based on existing patents or patents that may be granted in the future. We may not be aware of all such intellectual
property rights potentially relating to our product candidates and their uses. Thus, we do not know with certainty that EBI-005 or any other product candidate, or our commercialization thereof, does not and will not infringe or otherwise violate any
third partys intellectual property.

If we
are found to infringe a third partys intellectual property rights, we could be required to obtain a license from such third party to continue developing and marketing our products and technology. However, we

may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors
access to the same technologies licensed to us. We could be forced, including by court order, to cease commercializing the infringing technology or product. In addition, we could be found liable for monetary damages, including treble damages and
attorneys fees if we are found to have willfully infringed a patent. A finding of infringement could prevent us from commercializing our product candidates or force us to cease some of our business operations. Claims that we have
misappropriated the confidential information or trade secrets of third parties could have a similar negative impact on our business.

If we fail to comply with our obligations in our intellectual property licenses and funding arrangements with third parties, we
could lose rights that are important to our business.

We are party to a number of license agreements and a collaboration agreement that impose, and, for a variety of purposes, we will likely enter into additional licensing and funding arrangements with third
parties that may impose, diligence, development and commercialization timelines and milestone payment, royalty, insurance and other obligations on us. Under certain of our existing licensing agreements, we are obligated to pay royalties or make
specified milestone payments on net product sales of product candidates or related technologies to the extent they are covered by the agreement. We also are obligated under certain of our existing license agreements to pay maintenance and other
fees. We also have diligence and development obligations under certain of those agreements that we are required to satisfy. If we fail to comply with our obligations under current or future license and collaboration agreements, our counterparties
may have the right to terminate these agreements, in which event we might not be able to develop, manufacture or market any product that is covered by these agreements or may face other penalties under the agreements. Such an occurrence could
diminish the value of the product candidate being developed under any such agreement. Termination of these agreements or reduction or elimination of our rights under these agreements may result in our having to negotiate new or reinstated agreements
with less favorable terms, or cause us to lose our rights under these agreements, including our rights to important intellectual property or technology.

We may be subject to claims by third parties asserting that our employees or we have misappropriated their intellectual property, or
claiming ownership of what we regard as our own intellectual property.

Many of our employees were previously employed at universities or other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although we try to ensure that our
employees do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that these employees or we have used or disclosed intellectual property, including trade secrets or other proprietary
information, of any such employees former employer. Litigation may be necessary to defend against these claims.

In addition, while it is our policy to require our employees and contractors who may be involved in the development of intellectual
property to execute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who in fact develops intellectual property that we regard as our own. Our and their assignment
agreements may not be self-executing or may be breached, and we may be forced to bring claims against third parties, or defend claims they may bring against us, to determine the ownership of what we regard as our intellectual property.

If we fail in prosecuting or defending any such claims, in
addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in prosecuting or defending against such claims, litigation could result in substantial costs and be a distraction to
management.

Intellectual property
litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities.

Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur
significant expenses, and could distract our technical and management personnel from

their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or
investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. Such litigation or proceedings could substantially increase our operating losses and reduce the resources available for
development activities or any future sales, marketing or distribution activities. We may not have sufficient financial or other resources to conduct such litigation or proceedings adequately. Some of our competitors may be able to sustain the costs
of such litigation or proceedings more effectively than we can because of their greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could compromise our ability to
compete in the marketplace.

If we are
unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patents for some of our technology and product candidates, we also rely on trade secrets, including unpatented
know-how, technology and other proprietary information, to maintain our competitive position. We seek to protect these trade secrets, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to them, such
as our employees, corporate collaborators, outside scientific collaborators, contract manufacturers, consultants, advisors and other third parties. We also enter into confidentiality and invention or patent assignment agreements with our employees
and consultants. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. Enforcing a claim
that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and outside the United States are less willing or unwilling to protect
trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them, or those to whom they communicate it, from using that technology or information to compete
with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed.

If we are not able to obtain required regulatory
approvals, we will not be able to commercialize EBI-005 or any other product candidate that we may develop, and our ability to generate revenue will be materially impaired. The marketing approval process is expensive, time-consuming and uncertain.
As a result, we cannot predict when or if we, or any collaborators we may have in the future, will obtain marketing approval to commercialize EBI-005 or any other product candidate.

The activities associated with the development and commercialization of our product candidates, including
EBI-005, including design, testing, manufacture, safety, efficacy, recordkeeping, labeling, storage, approval, advertising, promotion, sale and distribution, are subject to comprehensive regulation by the FDA and other regulatory agencies in the
United States and by the EMA and similar regulatory authorities outside the United States. Failure to obtain marketing approval for a product candidate will prevent us from commercializing the product candidate. We have not received approval to
market EBI-005 or any other product candidate from regulatory authorities in any jurisdiction. We have only limited experience in filing and supporting the applications necessary to gain marketing approvals and expect to rely on third-party CROs to
assist us in this process.

The process of
obtaining marketing approvals, both in the United States and abroad, is expensive and may take many years, especially if additional clinical trials are required, if approval is obtained at all. Securing marketing approval requires the submission of
extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidates safety, purity and potency. Securing marketing approval also requires the
submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. The FDA or

other regulatory authorities may determine that EBI-005 or any other product candidate that we may develop is not safe, effective or pure, is only moderately effective or has undesirable or
unintended side effects, toxicities or other characteristics that preclude our obtaining marketing approval or prevent or limit commercial use. Any marketing approval we ultimately obtain may be limited or subject to restrictions or post-approval
commitments that render the approved product not commercially viable.

The regulatory process can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. There are no drugs approved in the European
Union and no drugs, other than Restasis, approved in the United States for the treatment of a sign or symptom of moderate to severe dry eye disease. The EMA has not issued any guidance on the clinical trials that would be sufficient to support an
application for marketing approval of a drug to treat dry eye disease. This lack of a defined regulatory pathway in the European Union and the lack of successful development of therapies to treat dry eye disease in both the United States and the
European Union may lengthen the regulatory review process, require us to conduct additional studies or clinical trials, increase our development costs, lead to changes in regulatory positions and interpretations, delay or prevent approval and
commercialization of these product candidates or lead to significant post-approval limitations or restrictions. If we experience delays in obtaining approval, the commercial prospects for our product candidates may be harmed and our ability to
generate revenues will be materially impaired.

We may not be able to obtain orphan drug exclusivity for one or more of our product candidates, and even if we do, that exclusivity
may not prevent the FDA or the EMA from approving other competing products.

Under the Orphan Drug Act, the FDA may designate a product as an orphan drug if it is a drug or biologic intended to treat a rare disease or condition. A similar regulatory scheme governs approval of
orphan products by the EMA in the European Union. Generally, if a product with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of
marketing exclusivity, which precludes the EMA or the FDA from approving another marketing application for the same product for the same therapeutic indication for that time period. The applicable period is seven years in the United States and ten
years in the European Union. The exclusivity period in the European Union can be reduced to six years if a product no longer meets the criteria for orphan drug designation, in particular if the product is sufficiently profitable so that market
exclusivity is no longer justified.

In order for
the FDA to grant orphan drug exclusivity to one of our products, the agency must find that the product is indicated for the treatment of a condition or disease with a patient population of fewer than 200,000 individuals annually in the United
States. The FDA may conclude that the condition or disease for which we seek orphan drug exclusivity does not meet this standard. Even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from
competition because different products can be approved for the same condition. In addition, even after an orphan drug is approved, the FDA can subsequently approve the same product for the same condition if the FDA concludes that the later product
is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care.

Our therapeutic product candidates for which we intend to seek approval as biological products may face competition sooner than
expected.

With the enactment of the
Biologics Price Competition and Innovation Act of 2009, or BPCIA, abbreviated pathways for approval of biosimilar and interchangeable biological products were created. The BPCIA establishes legal authority for the FDA to review and approve
biosimilar biologics for marketing, as well as biosimilars that have been designated as interchangeable with a previously approved biologic, or reference product. Under the BPCIA, an application for a biosimilar product cannot be
approved by the FDA until 12 years after the reference product was approved under a full BLA. This period of non-patent exclusivity runs concurrently with, but is independent of, periods of patent protection for the reference product.

We believe that any of our product candidates approved as a biological product under a full
BLA should qualify for a 12-year period of exclusivity. However:

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the U.S. Congress could amend the BPCIA to significantly shorten this exclusivity period as has been previously proposed by President Obama in
connection with the administrations budget proposals; and

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a potential competitor could seek and obtain approval of its own BLA during our exclusivity period instead of seeking approval of a biosimilar version.

The new law is complex and is
only beginning to be interpreted and implemented by the FDA. As a result, the ultimate impact, implementation and meaning of the BPCIA is subject to uncertainty. While it is uncertain when any such processes may be fully adopted by the FDA, any such
processes could compromise the future commercial prospects for our biological products. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of our reference products in a way that is similar to traditional
generic substitution for non-biological products is not yet clear and will depend on a number of marketplace and regulatory factors that are still developing at both the federal and state levels of government.

Failure to obtain marketing approval in international
jurisdictions would prevent our product candidates from being marketed abroad.

In order to market and sell EBI-005 and any other product candidate that we may develop in the European Union and many other jurisdictions, we or our third-party collaborators must obtain separate
marketing approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among countries and can involve additional testing. The time required to obtain approval may differ substantially from that required to
obtain FDA approval. The regulatory approval process outside the United States generally includes all of the risks associated with obtaining FDA approval. In addition, in many countries outside the United States, it is required that the product be
approved for reimbursement before the product can be sold in that country. We or these third parties may not obtain approvals from regulatory authorities outside the United States on a timely basis, if at all. Approval by the FDA does not ensure
approval by regulatory authorities in other countries or jurisdictions, and approval by one regulatory authority outside the United States does not ensure approval by regulatory authorities in other countries or jurisdictions or by the FDA. We may
not be able to file for marketing approvals and may not receive necessary approvals to commercialize our products in any market.

Even if we, or any collaborators we may have in the future, obtain marketing approvals for EBI-005 or our other product candidates,
the terms of those approvals, ongoing regulations and post-marketing restrictions may limit how we, or they, manufacture and market our products, which could materially impair our ability to generate revenue.

Once marketing approval has been granted, an approved
product and its manufacturer and marketer are subject to ongoing review and extensive regulation. We, and any collaborators we may have in the future, must therefore comply with requirements concerning advertising and promotion for any of our
products for which we or they obtain marketing approval. Promotional communications with respect to prescription products are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the products
approved labeling. Thus, if EBI-005 or any other product candidate that we may develop receives marketing approval, the accompanying label may limit the approved use of our product, which could limit sales of the product.

In addition, manufacturers of approved products and those
manufacturers facilities are required to comply with extensive FDA requirements, including ensuring that quality control and manufacturing procedures conform to cGMPs, which include requirements relating to quality control and quality
assurance as well as the corresponding maintenance of records and documentation and reporting requirements. We, our contract manufacturers, our future collaborators and their contract manufacturers will also be subject to other regulatory
requirements, including submissions of safety and other post-marketing information and reports, registration and listing requirements, requirements regarding the distribution of samples to physicians, recordkeeping, and costly

post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of the product such as the requirement to implement a risk evaluation and mitigation strategy.

We may be subject to substantial penalties
if we fail to comply with regulatory requirements or if we experience unanticipated problems with our products.

Violations of the Federal Food, Drug, and Cosmetic Act relating to the promotion or manufacturing of prescription products may lead to
investigations by the FDA, Department of Justice and state Attorneys General alleging violations of federal and state healthcare fraud and abuse laws, as well as state consumer protection laws. In addition, later discovery of previously unknown
adverse events or other problems with our products, manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may yield various results, including:

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restrictions on such products, manufacturers or manufacturing processes;

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restrictions on the labeling or marketing of a product;

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restrictions on product distribution or use;

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requirements to conduct post-marketing studies or clinical trials;

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warning letters;

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withdrawal of the products from the market;

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refusal to approve pending applications or supplements to approved applications that we submit;

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recall of products;

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fines, restitution or disgorgement of profits or revenues;

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suspension or withdrawal of marketing approvals;

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refusal to permit the import or export of our products;

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product seizure; or

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injunctions or the imposition of civil or criminal penalties.

Non-compliance with European Union requirements regarding
safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, can also result in significant financial penalties.

Our relationships with customers and third-party payors may be subject, directly or indirectly, to
applicable anti-kickback, fraud and abuse, false claims, transparency, health information privacy and security, and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, contractual damages,
reputational harm, administrative burdens and diminished profits and future earnings.

Healthcare providers, physicians and third-party payors in the United States and elsewhere will play a primary role in the recommendation and prescription of any product candidates, including EBI-005, for
which we obtain marketing approval. Our future arrangements with third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements
and relationships through which we market, sell and distribute any products for which we obtain marketing approval. In addition, we may be subject to transparency laws and patient privacy regulation by U.S. federal and state governments and by
governments in foreign jurisdictions in which we conduct our business. The applicable federal, state and foreign healthcare laws and regulations that may affect our ability to operate include:

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the federal Anti-Kickback Statute, which prohibits, among other things, persons from knowingly and willfully soliciting, offering, receiving or
providing remuneration, directly or indirectly, in cash or in kind,

to induce or reward, or in return for, either the referral of an individual for, or the purchase, order or recommendation of, any good or service, for which payment may be made under a federal
healthcare program such as Medicare and Medicaid;

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federal civil and criminal false claims laws and civil monetary penalty laws, including the federal False Claims Act, which impose criminal and civil
penalties, including civil whistleblower or qui tam actions, against individuals or entities for knowingly presenting, or causing to be presented, to the federal government, including the Medicare and Medicaid programs, claims for payment
that are false or fraudulent or making a false statement to avoid, decrease or conceal an obligation to pay money to the federal government;

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the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which imposes criminal and civil liability for executing a scheme to
defraud any healthcare benefit program or making false statements relating to healthcare matters;

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HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act of 2009, and their respective implementing regulations,
which imposes obligations, including mandatory contractual terms, on covered healthcare providers, health plans and healthcare clearinghouses, as well as their business associates, with respect to safeguarding the privacy, security and transmission
of individually identifiable health information; and

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analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, which may apply to sales or marketing arrangements
and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers; state and foreign laws that require pharmaceutical companies to comply with the pharmaceutical industrys voluntary
compliance guidelines and the relevant compliance guidance promulgated by the federal government or otherwise restrict payments that may be made to healthcare providers; state and foreign laws that require drug manufacturers to report information
related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures; and state and foreign laws governing the privacy and security of health information in certain circumstances, many of which
differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations may
involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws
and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, including, without
limitation, damages, fines, imprisonment, exclusion from participation in government funded healthcare programs, such as Medicare and Medicaid, and the curtailment or restructuring of our operations. If any of the physicians or other healthcare
providers or entities with whom we expect to do business is found to be not in compliance with applicable laws, it may be subject to criminal, civil or administrative sanctions, including exclusions from participation in government funded healthcare
programs.

Recently enacted and future
legislation may affect our ability to commercialize and the prices we obtain for any products that are approved in the United States or foreign jurisdictions.

In the United States and some foreign jurisdictions, there
have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could affect our ability to profitably sell or commercialize any product candidate, including EBI-005, for which we obtain marketing
approval or that we may in-license. The pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by legislative initiatives. Current laws, as well as other healthcare reform measures that may be
adopted in the future, may result in more rigorous coverage criteria and in additional downward pressure on the price that we receive for any approved product.

In the United States, the Medicare Prescription Drug, Improvement, and Modernization Act of
2003, or the MMA, changed the way Medicare covers and pays for pharmaceutical products. Cost reduction initiatives and other provisions of this legislation could limit coverage of and reduce the price that we receive for any approved products. While
the MMA applies only to product benefits for Medicare beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates. Therefore, any reduction in reimbursement that results from
the MMA or other healthcare reform measures may result in a similar reduction in payments from private payors.

In March 2010, President Obama signed into law the Patient Protection and Affordable Care Act, as amended by the Health Care and Education
Affordability Reconciliation Act, or collectively PPACA. Among the provisions of PPACA of importance to our business, including, without limitation, our ability to commercialize and the prices we may obtain for any of our product candidates and that
are approved for sale, are the following:

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an annual, nondeductible fee on any entity that manufactures or imports specified branded prescription drugs and biologic agents;

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an increase in the statutory minimum rebates a manufacturer must pay under the Medicaid Drug Rebate Program;

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a new Medicare Part D coverage gap discount program, in which participating manufacturers must agree to offer 50% point-of-sale discounts off
negotiated drug prices during the coverage gap period as a condition for the manufacturers outpatient drugs to be covered under Medicare Part D;

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expansion of healthcare fraud and abuse laws, including the federal False Claims Act and the federal Anti-Kickback Statute, and the addition of new
government investigative powers, and enhanced penalties for noncompliance;

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extension of manufacturers Medicaid rebate liability;

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expansion of eligibility criteria for Medicaid programs; and

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expansion of the entities eligible for discounts under the Public Health Service pharmaceutical pricing program.

In addition, other legislative changes have been proposed and
adopted since PPACA was enacted. These changes include aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, which went into effect in April 2013. In January 2013, President Obama signed into law the
American Taxpayer Relief Act of 2012, which, among other things, reduced Medicare payments to several types of providers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five
years. These new laws may result in additional reductions in Medicare and other healthcare funding.

The pricing of prescription pharmaceuticals is also subject to governmental control outside the United States. In these countries, pricing
negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares
the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our ability to generate revenues and become
profitable could be impaired.

Laws and
regulations governing any international operations we may have in the future may preclude us from developing, manufacturing and selling certain products outside of the United States and require us to develop and implement costly compliance programs.

If we expand our operations outside of
the United States, we must dedicate additional resources to comply with numerous laws and regulations in each jurisdiction in which we plan to operate. The Foreign Corrupt Practices Act, or FCPA, prohibits any U.S. individual or business from
paying, offering, authorizing payment or

offering of anything of value, directly or indirectly, to any foreign official, political party or candidate for the purpose of influencing any act or decision of the foreign entity in order to
assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the United States to comply with certain accounting provisions requiring the company to maintain books and records
that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls for international operations.

Compliance with the FCPA is expensive and difficult,
particularly in countries in which corruption is a recognized problem. In addition, the FCPA presents particular challenges in the pharmaceutical industry, because, in many countries, hospitals are operated by the government, and doctors and other
hospital employees are considered foreign officials. Certain payments to hospitals in connection with clinical trials and other work have been deemed to be improper payments to government officials and have led to FCPA enforcement actions.

Various laws, regulations and executive orders
also restrict the use and dissemination outside of the United States, or the sharing with certain non-U.S. nationals, of information classified for national security purposes, as well as certain products and technical data relating to those
products. If we expand our presence outside of the United States, it will require us to dedicate additional resources to comply with these laws, and these laws may preclude us from developing, manufacturing, or selling certain products and product
candidates outside of the United States, which could limit our growth potential and increase our development costs.

The failure to comply with laws governing international business practices may result in substantial civil and criminal penalties and
suspension or debarment from government contracting. The Securities and Exchange Commission also may suspend or bar issuers from trading securities on U.S. exchanges for violations of the FCPAs accounting provisions.

If we or our third-party manufacturers fail to comply
with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur significant costs.

We and our third-party manufacturers are subject to numerous environmental, health and safety laws and regulations, including those
governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. From time to time and in the future, our operations may involve the use of hazardous and flammable materials, including
chemicals and biological materials, and produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the
event of contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal
fines and penalties for failure to comply with such laws and regulations.

Although we maintain workers compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, this insurance may
not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological, hazardous or
radioactive materials.

In addition, we may incur
substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Our failure to comply with
these laws and regulations also may result in substantial fines, penalties or other sanctions.

Further, with respect to the operations of our third-party contract manufacturers, it is possible that if they fail to operate in compliance with applicable environmental, health and safety laws and
regulations or properly dispose of wastes associated with our products, we could be held liable for any resulting damages, suffer

We are highly dependent on the research and development, clinical and business development expertise of Abbie Celniker, Ph.D., our President and Chief Executive Officer, Gregory D. Perry, our Chief
Financial and Business Officer, Eric Furfine, Ph.D., our Chief Scientific Officer, and Karen L. Tubridy, our Chief Development Officer, as well as the other principal members of our management, scientific and clinical team. Although we have entered
into employment agreements with our executive officers, each of them may terminate their employment with us at any time. We do not maintain key person insurance for any of our executives or other employees.

Recruiting and retaining qualified scientific, clinical,
manufacturing and sales and marketing personnel will also be critical to our success. The loss of the services of our executive officers or other key employees could impede the achievement of our research, development and commercialization
objectives and seriously harm our ability to successfully implement our business strategy. Furthermore, replacing executive officers and key employees may be difficult and may take an extended period of time because of the limited number of
individuals in our industry with the breadth of skills and experience required to successfully develop, gain regulatory approval of and commercialize products. Competition to hire from this limited pool is intense, and we may be unable to hire,
train, retain or motivate these key personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for similar personnel. We also experience competition for the hiring of scientific and clinical
personnel from universities and research institutions. In addition, we rely on consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and development and commercialization strategy. Our
consultants and advisors may be employed by employers other than us and may have commitments under consulting or advisory contracts with other entities that may limit their availability to us. If we are unable to continue to attract and retain high
quality personnel, our ability to pursue our growth strategy will be limited.

We expect to expand our development and regulatory capabilities and potentially implement sales, marketing and distribution capabilities, and as a result, we may encounter difficulties in managing
our growth, which could disrupt our operations.

We expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of drug development, regulatory affairs and, if any of our product
candidates receives marketing approval, sales, marketing and distribution. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to
recruit and train additional qualified personnel. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of
our operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the
execution of our business plans or disrupt our operations.

Risks Related to Our Common Stock and This Offering

After this offering, our executive officers, directors and principal stockholders, if they choose to act together, will continue to
have the ability to control all matters submitted to stockholders for approval.

Upon the closing of this offering, our executive officers and directors, combined with our stockholders who owned more than 5% of our outstanding common stock, before this offering will, in the aggregate,
beneficially

own shares representing approximately 52.5% of our capital stock. Assuming an initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover
page of this prospectus, if certain of our preferred stockholders, including our existing principal stockholders, and their affiliated entities purchase all the shares they have indicated an interest in purchasing in this offering, the number of
shares of our common stock beneficially owned by our executive officers, directors and principal stockholders will, in the aggregate, increase to 58.0% of our capital stock. As a result, if these stockholders were to choose to act together, they
would be able to control all matters submitted to our stockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would control the election of directors and approval of any merger,
consolidation or sale of all or substantially all of our assets.

This concentration of voting power may:



delay, defer or prevent a change in control;



entrench our management and the board of directors; or



delay or prevent a merger, consolidation, takeover or other business combination involving us on terms that other stockholders may desire.

Provisions in our
corporate charter documents and under Delaware law could make an acquisition of our company, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.

Provisions in our certificate of
incorporation and our bylaws that will become effective upon the closing of this offering may discourage, delay or prevent a merger, acquisition or other change in control of our company that stockholders may consider favorable, including
transactions in which you might otherwise receive a premium for your shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of our
common stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by
making it more difficult for stockholders to replace members of our board of directors. Among other things, these provisions:



establish a classified board of directors such that only one of three classes of directors is elected each year;



allow the authorized number of our directors to be changed only by resolution of our board of directors;



limit the manner in which stockholders can remove directors from our board of directors;



establish advance notice requirements for stockholder proposals that can be acted on at stockholder meetings and nominations to our board of directors;



require that stockholder actions must be effected at a duly called stockholder meeting and prohibit actions by our stockholders by written consent;



limit who may call stockholder meetings;



authorize our board of directors to issue preferred stock without stockholder approval, which could be used to institute a poison pill that
would work to dilute the stock ownership of a potential hostile acquirer, effectively preventing acquisitions that have not been approved by our board of directors; and



require the approval of the holders of at least 75% of the votes that all our stockholders would be entitled to cast to amend or repeal specified
provisions of our certificate of incorporation or bylaws that will become effective upon the closing of this offering.

Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General
Corporation Law, which prohibits a person who owns in excess of 15% of our outstanding

voting stock from merging or combining with us for a period of three years after the date of the transaction in which the person acquired in excess of 15% of our outstanding voting stock, unless
the merger or combination is approved in a prescribed manner.

If you purchase shares of common stock in this offering, you will suffer immediate dilution of your investment.

The initial public offering price of our common stock
will be substantially higher than the pro forma net tangible book value per share of our common stock. Therefore, if you purchase shares of our common stock in this offering, you will pay a price per share that substantially exceeds our pro forma
net tangible book value per share after this offering. To the extent outstanding options or warrants are exercised, you will incur further dilution. Based on an assumed initial public offering price of $14.00 per share, which is the midpoint of
the price range set forth on the cover page of this prospectus, you will experience immediate dilution of $9.95 per share, representing the difference between our pro forma net tangible book value per share, after giving effect to this
offering, and the assumed initial public offering price. In addition, purchasers of common stock in this offering will have contributed approximately 50.9% of the aggregate price paid for all purchases of our stock but the shares purchased in this
offering will represent an aggregate of only approximately 29.3% of our total common stock outstanding after this offering.

An active trading market for our common stock may not develop.

Prior to this offering, there has been no public market for our common stock. The initial public offering price
for our common stock will be determined through negotiations with the underwriters. Although we have applied to have our common stock approved for listing on The NASDAQ Global Market, an active trading market for our shares may never develop or be
sustained following this offering. If an active market for our common stock does not develop, it may be difficult for you to sell shares you purchase in this offering without depressing the market price for the shares or at all.

The price of our common stock may be volatile and
fluctuate substantially, which could result in substantial losses for purchasers of our common stock in this offering.

Our stock price is likely to be volatile. The stock market in general and the market for smaller biopharmaceutical companies in particular
have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. As a result of this volatility, you may not be able to sell your common stock at or above the initial public offering price. The
market price for our common stock may be influenced by many factors, including:



the success of competitive products or technologies;



results of clinical trials of EBI-005 or any other product candidate that we may develop;



results of clinical trials of product candidates of our competitors;



regulatory or legal developments in the United States and other countries;

the recruitment or departure of key scientific or management personnel;



the level of expenses related to any of our product candidates or clinical development programs;



the results of our efforts to discover, develop, acquire or in-license additional products, product candidates or technologies for the treatment of
ophthalmic diseases, the costs of commercializing any such products and the costs of development of any such product candidates or technologies;



actual or anticipated changes in estimates as to financial results, development timelines or recommendations by securities analysts;

variations in our financial results or those of companies that are perceived to be similar to us;



changes in the structure of healthcare payment systems;



market conditions in the pharmaceutical and biotechnology sectors;



general economic, industry and market conditions; and



the other factors described in this Risk Factors section.

In the past, following periods of volatility in the market price of a companys securities, securities
class-action litigation has often been instituted against that company. We also may face securities class-action litigation if we cannot obtain regulatory approvals for or if we otherwise fail to commercialize EBI-005. Such litigation, if instituted
against us, could cause us to incur substantial costs to defend such claims and divert managements attention and resources.

We have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

Our management will have broad discretion in the application
of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our common stock. The failure by our management to apply these funds effectively could result in
financial losses that could cause the price of our common stock to decline and delay the development of our product candidates. Pending their use, we may invest the net proceeds from this offering in a manner that does not produce income or that
loses value.

Our ability to use our net
operating loss carryforwards and certain other tax attributes may be limited.

As of December 31, 2012, we had federal net operating loss carryforwards of $37.9 million, state net operating loss carryforwards of $37.4 million and aggregate federal and state research and development
tax credit carryforwards of $0.9 million available to reduce future taxable income. These federal and state net operating loss carryforwards and federal and state tax credit carryforwards will begin to expire at various dates beginning in 2014, if
not utilized. Utilization of these net operating loss and tax credit carryforwards may be subject to a substantial limitation under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, or the Code, and comparable provisions of
state, local and foreign tax laws due to changes in ownership of our company that have occurred previously or that could occur in the future. Under Section 382 of the Code and comparable provisions of state, local and foreign tax laws, if a
corporation undergoes an ownership change, generally defined as a greater than 50% change by value in its equity ownership over a three year period, the corporations ability to use its pre-change net operating loss carryforwards
and other pre-change tax attributes, such as research and development tax credits, to reduce its post-change income may be limited. We have not completed a study to determine whether our initial public offering, our most recent private placement of
our series B preferred stock and warrants to purchase shares of our common stock and other transactions that have occurred over the past three years may have triggered an ownership change limitation. We may also experience ownership changes in the
future as a result of subsequent shifts in our stock ownership. As a result, if we generate taxable income, our ability to use our pre-change net operating loss and tax credits carryforwards to reduce U.S. federal and state taxable income may be
subject to limitations, which could result in increased future tax liability to us.

A significant portion of our total outstanding shares are eligible to be sold into the market in the near future, which could cause the market price of our common stock to drop significantly, even
if our business is doing well.

Sales
of a substantial number of shares of our common stock in the public market, or the perception in the market that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock. After this offering,
we will have 14,693,713 shares of common stock outstanding based on the

number of shares outstanding as of January 21, 2014. This includes the shares that we are selling in this offering, which may be resold in the public market immediately without restriction,
unless purchased by our affiliates or existing stockholders. The remaining 10,393,713 shares are currently restricted as a result of securities laws or lock-up agreements but will become eligible to be sold at various times after the offering.
Moreover, after this offering, holders of an aggregate of 8,699,135 shares of our common stock will have rights, subject to specified conditions, to require us to file registration statements covering their shares or, along with holders of an
additional 30,708 shares of our common stock issuable upon exercise of warrants issued to our venture debt lender, to include their shares in registration statements that we may file for ourselves or other stockholders. We also intend to register
all shares of common stock that we may issue under our equity compensation plans. Once we register these shares, they can be freely sold in the public market upon issuance, subject to volume limitations applicable to affiliates and the lock-up
agreements described in the Underwriting section of this prospectus.

We are an emerging growth company, and the reduced disclosure requirements applicable to emerging growth companies may make our common stock less attractive to investors.

We are an emerging growth
company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and may remain an emerging growth company for up to five years. For so long as we remain an emerging growth company, we are permitted and intend to rely
on exemptions from certain disclosure requirements that are applicable to other public companies that are not emerging growth companies. These exemptions include:



being permitted to provide only two years of audited financial statements, in addition to any required unaudited interim financial statements, with
correspondingly reduced Managements Discussion and Analysis of Financial Condition and Results of Operations disclosure;



not being required to comply with the auditor attestation requirements in the assessment of our internal control over financial reporting;



not being required to comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit firm
rotation or a supplement to the auditors report providing additional information about the audit and the financial statements;



reduced disclosure obligations regarding executive compensation; and



exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute
payments not previously approved.

We have taken advantage of reduced reporting burdens in this prospectus. In particular, in this prospectus, we have provided only two
years of audited financial statements and have not included all of the executive compensation related information that would be required if we were not an emerging growth company. We cannot predict whether investors will find our common stock less
attractive if we rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

In addition, the JOBS Act also provides that an emerging
growth company can take advantage of an extended transition period for complying with new or revised accounting standards. This allows an emerging growth company to delay the adoption of certain accounting standards until those standards
would otherwise apply to private companies. We have irrevocably elected not to delay such adoption of new or revised accounting standards, and, as a result, we will comply with new or revised accounting standards on the relevant dates on which
adoption of such standards is required for public companies that are not emerging growth companies.

We will incur increased costs as a result of operating as a public company, and our management will be required to devote substantial time to new compliance initiatives and corporate governance
practices.

As a public company, and
particularly after we are no longer an emerging growth company, we will incur significant legal, accounting and other expenses that we did not incur as a private company. The Sarbanes-Oxley Act

of 2002, the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of The NASDAQ Global Market and other applicable securities rules and regulations impose various
requirements on public companies, including establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Our management and other personnel will need to devote a substantial amount of time to these
compliance initiatives. Moreover, these rules and regulations will increase our legal and financial compliance costs and will make some activities more time-consuming and costly. For example, we expect that these rules and regulations may make it
more difficult and more expensive for us to obtain director and officer liability insurance, which in turn could make it more difficult for us to attract and retain qualified members of our board of directors.

We are evaluating these rules and regulations, and cannot
predict or estimate the amount of additional costs we may incur or the timing of such costs. These rules and regulations are often subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their
application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure
and governance practices.

For as long as we
remain an emerging growth company, we may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies as described in the preceding risk factor. We may
remain an emerging growth company until the end of the fiscal year in which the fifth anniversary of this offering occurs, although if the market value of our common stock that is held by non-affiliates exceeds $700 million as of any June 30 before
that time or if we have annual gross revenues of $1 billion or more in any fiscal year, we would cease to be an emerging growth company as of December 31 of the applicable year. We also would cease to be an emerging growth company if we issue more
than $1 billion of non-convertible debt over a three-year period.

Pursuant to Section 404 of the Sarbanes-Oxley Act of 2002, or Section 404, we will be required to furnish a report by our management on our internal control over financial reporting. However,
while we remain an emerging growth company, we will not be required to include an attestation report on internal control over financial reporting issued by our independent registered public accounting firm. To achieve compliance with
Section 404 within the prescribed period, we will be engaged in a process to document and evaluate our internal control over financial reporting, which is both costly and challenging. In this regard, we will need to continue to dedicate
internal resources, potentially engage outside consultants and adopt a detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to improve control processes as appropriate, validate through
testing that controls are functioning as documented and implement a continuous reporting and improvement process for internal control over financial reporting. Despite our efforts, there is a risk that we will not be able to conclude, within the
prescribed timeframe or at all, that our internal control over financial reporting is effective as required by Section 404. If we identify one or more material weaknesses in our internal control over financial reporting, it could result in an
adverse reaction in the financial markets due to a loss of confidence in the reliability of our financial statements.

Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital appreciation, if any,
will be your sole source of gain.

We
have never declared or paid cash dividends on our capital stock. We currently intend to retain all of our future earnings, if any, to finance the growth and development of our business. In addition, the terms of our loan and security agreement with
Silicon Valley Bank and any future debt agreements that we may enter into, may preclude us from paying dividends without the lenders consent or at all. As a result, capital appreciation, if any, of our common stock will be your sole source of
gain for the foreseeable future.

The forward-looking statements in this prospectus include, among other things, statements about:



our plans to develop and commercialize EBI-005 and other protein therapeutics to treat diseases of the eye;



our ongoing and planned clinical trials, including the timing of the initiation and availability of anticipated top-line results of our two Phase 3
clinical trials evaluating EBI-005 for the treatment of moderate to severe dry eye disease;

We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place
undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary
statements included in this prospectus, particularly in the Risk Factors section, that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements
do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.

You should read this prospectus and the documents that we reference in this prospectus and have filed as exhibits to the registration
statement of which this prospectus is a part completely and with the understanding that our actual future results may be materially different from what we expect. The forward-looking statements contained in this prospectus are made as of the date of
this prospectus, and we do not assume any obligation to update any forward-looking statements.

We estimate that the net proceeds from our issuance and
sale of 4,300,000 shares of our common stock in this offering will be approximately $53.0 million, assuming an initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this
prospectus, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us. If the underwriters exercise their over-allotment option in full, we estimate that the net proceeds from this offering will
be approximately $61.4 million.

A $1.00 increase
or decrease in the assumed initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease the net proceeds from this offering by approximately
$4.0 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions.

As of September 30, 2013, we had cash and cash
equivalents of $3.9 million. In December 2013, we received $9.0 million in cash proceeds from our series B preferred stock financing. We currently estimate that we will use the net proceeds from this offering, together with our existing cash and
cash equivalents, as follows:



approximately $36 million to fund external research and development expenses for our pivotal Phase 3 clinical program for EBI-005 in patients with
moderate to severe dry eye disease and, if the results from this program are favorable, the submission of a Biologics License Application, or BLA, to the United States Food and Drug Administration, or FDA, seeking approval of EBI-005 for the
treatment of dry eye disease in the United States;



approximately $3 million to fund external research and development expenses for our Phase 2 clinical trial of EBI-005 in patients with allergic
conjunctivitis; and



the remainder for working capital and other general corporate purposes, which will include our internal research and development expenses for EBI-005,
development of our preclinical product candidates and pursuit of our other research and discovery efforts and could also include the acquisition or in-license of other products, product candidates or technologies.

This expected use of net proceeds from this offering and our
existing cash and cash equivalents represents our intentions based upon our current plans and business conditions, which could change in the future as our plans and business conditions evolve. The amounts and timing of our actual expenditures may
vary significantly depending on numerous factors, including the progress of our development, the status of and results from clinical trials, as well as any collaborations that we may enter into with third parties for our product candidates, and any
unforeseen cash needs. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering. We have no current agreements, commitments or understandings for any material acquisitions or licenses of any
products, businesses or technologies.

Based
on our planned use of the net proceeds from this offering and our existing cash and cash equivalents described above, we estimate that such funds will be sufficient to enable us to complete our pivotal Phase 3 clinical program for EBI-005 in
patients with moderate to severe dry eye disease, submit a BLA to the FDA seeking approval of EBI-005 for the treatment of dry eye disease in the United States in the second half of 2016 and complete our Phase 2 clinical trial of EBI-005 in patients
with allergic conjunctivitis. We do not anticipate that the net proceeds from this offering and our existing cash and cash equivalents will be sufficient to allow us to commercialize EBI-005.

Pending our use of the net proceeds from this offering, we
intend to invest the net proceeds in a variety of capital preservation investments, including short-term, investment-grade, interest-bearing instruments and U.S. government securities.

We have never declared or paid cash dividends on our common
stock. We currently intend to retain all of our future earnings, if any, to finance the growth and development of our business. We do not intend to pay cash dividends in respect of our common stock in the foreseeable future. In addition, the terms
of our existing loan and security agreement with Silicon Valley Bank preclude us from paying dividends without Silicon Valley Banks consent.

The following table sets forth our cash and
cash equivalents and capitalization as of September 30, 2013:



on an actual basis;



on a pro forma basis to give effect to:



the completion of our series B preferred stock financing in December 2013 in which we issued and sold an aggregate of 7,203,845 shares of our series B
preferred stock and warrants to purchase 202,472 shares of our common stock for an aggregate purchase price of $12.6 million, consisting of $9.0 million in cash and $3.6 million for the conversion of outstanding convertible promissory notes,
including accrued interest;



the automatic conversion of all outstanding shares of our preferred stock, including the shares of our series B preferred stock that we issued in
December 2013, into an aggregate of 8,260,444 shares of our common stock upon the closing of this offering;



the reclassification of our warrant liability to stockholders equity as a result of warrants to purchase preferred stock becoming warrants to
purchase common stock upon the closing of this offering; and



the issuance of 478,061 shares of our common stock upon the exercise of outstanding warrants held by some of our preferred stockholders, at an exercise
price of $0.06 per share, including shares of our common stock issuable upon the exercise of the warrants that we issued in December 2013, which otherwise expire upon the closing of this offering; and



on a pro forma as adjusted basis to give further effect to our issuance and sale of 4,300,000 shares of our common stock in this offering at an assumed
initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by
us.

Our capitalization
following the closing of this offering will be adjusted based on the actual initial public offering price and other terms of this offering determined at pricing. You should read this table together with Selected Financial Data, our
financial statements and the related notes appearing at the end of this prospectus and the Managements Discussion and Analysis of Financial Condition and Results of Operations section of this prospectus.

A $1.00 increase or decrease in the assumed initial public offering price of $14.00 per
share, which is the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease each of cash and cash equivalents, additional paid-in capital, total stockholders equity and total capitalization on a
pro forma as adjusted basis by approximately $4.0 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and
estimated offering expenses payable by us.

The table above does not include:



1,009,279 shares of our common stock issuable upon the exercise of stock options outstanding as of September 30, 2013 at a weighted average
exercise price of $0.95 per share;



30,708 shares of our common stock issuable following the closing of this offering upon the exercise of warrants outstanding as of September 30,
2013 held by our venture debt lender, Silicon Valley Bank, at an exercise price of $6.35 per share;



88,554 shares of our common stock available for future issuance under our 2009 Stock Incentive Plan as of September 30, 2013, plus an additional
259,843 shares of our common stock that were authorized for issuance under our 2009 Stock Incentive Plan on October 31, 2013;



708,661 additional shares of our common stock that will become available for future issuance under our 2014 Stock Incentive Plan upon the closing of
this offering;



14,694 shares of our common stock issuable upon the exercise of stock options to be granted under our 2014 Stock Incentive Plan to some of our
non-employee directors on the 30th trading day of our
common stock on The NASDAQ Global Market at an exercise price per share equal to the fair market value of our common stock on the date of the grant;



56,386 shares of our common stock to be granted to the chairman of our board of directors upon the closing of this offering under our 2014 Stock
Incentive Plan pursuant to a restricted stock agreement; and



157,480 additional shares of our common stock that will be available for future issuance under our employee stock purchase plan upon the closing of
this offering.

If you invest in our common stock in this offering, your
ownership interest will be diluted immediately to the extent of the difference between the public offering price per share of our common stock and the pro forma net tangible book value per share of our common stock after this offering.

Our historical net tangible book value (deficit) as of
September 30, 2013 was $(51.2) million, or $(31.11) per share of our common stock. Historical net tangible book value per share represents the amount of our total tangible assets less total liabilities and our series A preferred stock,
divided by the number of shares of our common stock outstanding as of September 30, 2013, which includes 210,499 shares of unvested restricted stock.

Our pro forma net tangible book value (deficit) as of September 30, 2013 was $6.5 million, or $0.63 per share of our common stock.
Pro forma net tangible book value per share represents the amount of our total tangible assets less our total liabilities, divided by the pro forma number of shares of our common stock outstanding as of September 30, 2013, which includes
210,499 shares of unvested restricted stock, after giving effect to the completion of our series B preferred stock financing in December 2013 in which we issued and sold an aggregate of 7,203,845 shares of our series B preferred stock and warrants
to purchase 202,472 shares of our common stock for an aggregate purchase price of $12.6 million, consisting of $9.0 million in cash and $3.6 million for the conversion of outstanding convertible promissory notes, including accrued interest, the
conversion of all outstanding shares of our preferred stock, including the shares of our series B preferred stock that we issued in December 2013, into an aggregate of 8,260,444 shares of our common stock upon the closing of this offering, the
related reclassification of our warrant liability to stockholders equity as a result of warrants to purchase preferred stock becoming warrants to purchase common stock upon the closing of this offering, and the issuance of 478,061 shares of
our common stock upon the exercise of outstanding warrants held by some of our preferred stockholders, at an exercise price of $0.06 per share, including shares of our common stock issuable upon the exercise of the warrants that we issued in
December 2013, which otherwise expire upon the closing of this offering.

After giving effect to our issuance and sale of 4,300,000 shares of our common stock in this offering at an assumed initial public offering price of $14.00 per share, which is the midpoint of the price
range set forth on the cover page of this prospectus, and after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma net tangible book value as of September 30, 2013 would have
been $59.5 million, or $4.05 per share. This represents an immediate increase in pro forma net tangible book value per share of $3.42 to existing stockholders and immediate dilution of $9.95 in pro forma net tangible book value per share to new
investors purchasing common stock in this offering. Dilution per share to new investors is determined by subtracting pro forma net tangible book value per share after this offering from the initial public offering price per share paid by new
investors. The following table illustrates this dilution on a per share basis:

Assumed initial public offering price per share

$

14.00

Historical net tangible book value (deficit) per share as of September 30, 2013

$

(31.11

)

Increase per share attributable to the issuance and sale of preferred stock and warrants to purchase common stock, the conversion
of outstanding preferred stock, the reclassification of warrant liability to stockholders equity and the exercise of common stock warrants

31.74

Pro forma net tangible book value (deficit) per share as of September 30, 2013

0.63

Increase in net tangible book value per share attributable to new investors

3.42

Pro forma net tangible book value per share after this offering

4.05

Dilution per share to new investors

$

9.95

A $1.00 increase or
decrease in the assumed initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease our pro forma net tangible book value by approximately
$4.0 million, our pro forma net tangible book value per share after this offering by approximately $0.28 and dilution per share to new investors by approximately $0.72, assuming that the

number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and estimated offering
expenses payable by us.

If the underwriters
exercise their over-allotment option or if any additional shares are issued in connection with the exercise of options, you will experience further dilution.

The following table summarizes, on a pro forma basis as of September 30, 2013, the total number of shares purchased from us on an
as converted to common stock basis, the total consideration paid, or to be paid, and the average price per share paid, or to be paid, by existing stockholders and by new investors in this offering at an assumed initial public offering price of
$14.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, before deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us. As the table shows, new
investors purchasing shares in this offering will pay an average price per share substantially higher than our existing stockholders paid.

Shares purchased

Total consideration

Number

Percentage

Amount

Percentage

Average priceper share

Existing stockholders

10,383,890

70.7

%

$

58,028,576

49.1

%

$

5.59

New investors

4,300,000

29.3

60,200,000

50.9

14.00

Total

14,683,890

100.0

%

$

118,228,576

100.0

%

A $1.00 increase or
decrease in the assumed initial public offering price of $14.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease the total consideration paid by new investors by $4.3
million and increase or decrease the percentage of total consideration paid by new investors by approximately 1.8 percentage points, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the
same.

The table above is based on shares
outstanding as of September 30, 2013, including 210,499 shares of unvested restricted stock, and after giving effect to our issuance and sale in December 2013 of 7,203,845 shares of our series B preferred stock and warrants to purchase 202,472
shares of our common stock, the automatic conversion of all outstanding shares of our preferred stock, including the shares of our series B preferred stock that we issued in December 2013, into an aggregate of 8,260,444 shares of our common stock
upon the closing of this offering and the issuance of 478,061 shares of our common stock issuable upon the exercise of outstanding warrants held by some of our preferred stockholders, at an exercise price of $0.06 per share, including shares of our
common stock issuable upon the exercise of the warrants that we issued in December 2013, which otherwise expire upon the closing of this offering.

The table above does not include:



1,009,279 shares of our common stock issuable upon the exercise of stock options outstanding as of September 30, 2013 at a weighted average
exercise price of $0.95 per share;



30,708 shares of our common stock issuable following the closing of this offering upon the exercise of warrants outstanding as of September 30,
2013 held by our venture debt lender, Silicon Valley Bank, at an exercise price of $6.35 per share;



88,554 shares of our common stock available for future issuance under our 2009 Stock Incentive Plan, as of September 30, 2013, plus an additional
259,843 shares of our common stock that were authorized for issuance under our 2009 Stock Incentive Plan on October 31, 2013;



708,661 additional shares of our common stock that will become available for future issuance under our 2014 Stock Incentive Plan upon the closing of
this offering;



14,694 shares of our common stock issuable upon the exercise of stock options to be granted under our 2014 Stock Incentive Plan to some of our
non-employee directors on the 30th trading day of our

common stock on The NASDAQ Global Market at an exercise price per share equal to the fair market value of our common stock on the date of the grant;



56,386 shares of our common stock to be granted to the chairman of our board of directors upon the closing of this offering under our 2014 Stock
Incentive Plan pursuant to a restricted stock agreement; and



157,480 additional shares of our common stock that will be available for future issuance under our employee stock purchase plan upon the closing of
this offering.

If the
underwriters exercise their over-allotment option in full, the following will occur:



the percentage of shares of our common stock held by existing stockholders will decrease to approximately 67.7% of the total number of shares of our
common stock outstanding after this offering; and



the percentage of shares of our common stock held by new investors will increase to approximately 32.3% of the total number of shares of our common
stock outstanding after this offering.

Certain of our preferred stockholders, including our existing principal stockholders, and their affiliated entities have indicated an interest in purchasing an aggregate of approximately $12 million in
shares of our common stock in this offering at the initial public offering price. However, because indications of interest are not binding agreements or commitments to purchase, these stockholders may determine to purchase fewer shares than they
indicate an interest in purchasing or not to purchase any shares in this offering. It is also possible that these stockholders could indicate an interest in purchasing more shares of our common stock. In addition, the underwriters could determine to
sell fewer shares to any of these stockholders than the stockholders indicate an interest in purchasing or not to sell any shares to these stockholders. The foregoing discussion and tables do not reflect any potential purchases by these stockholders
or their affiliated entities.

You should read the following selected financial data
together with our financial statements and the related notes appearing at the end of this prospectus and the Managements Discussion and Analysis of Financial Condition and Results of Operations section of this prospectus. We have
derived the statement of operations data for the years ended December 31, 2011 and 2012 and the balance sheet data as of December 31, 2011 and 2012 from our audited financial statements included in this prospectus, which have been audited
by Ernst & Young LLP, an independent registered public accounting firm. We have derived the statement of operations data for the nine months ended September 30, 2012 and 2013 and the balance sheet data as of September 30, 2013
from our unaudited financial statements included in this prospectus. The unaudited financial data include, in the opinion of our management, all adjustments, consisting of normal recurring adjustments, that are necessary for a fair statement of our
financial position and results of operations for these periods. Our historical results for any prior period are not necessarily indicative of results to be expected in any future period, and our results for any interim period are not necessarily
indicative of results to be expected for a full fiscal year.

Year endedDecember 31,

Nine months endedSeptember 30,

2011

2012

2012

2013

(in thousands, except per share data)

Statement of Operations Data:

Collaboration revenue

$



$



$



$

824

Operating expenses:

Research and development

9,411

15,263

11,367

10,576

General and administrative

3,267

4,213

3,081

2,606

Total operating expenses

12,678

19,476

14,448

13,182

Loss from operations

(12,678

)

(19,476

)

(14,448

)

(12,358

)

Other income (expense):

Other income (expense), net

3

(13

)

7

(96

)

Interest expense

(151

)

(168

)

(122

)

(505

)

Total other expense, net

(148

)

(181

)

(115

)

(601

)

Net loss and comprehensive loss

$

(12,826

)

$

(19,657

)

$

(14,563

)

$

(12,959

)

Cumulative preferred stock dividends

(1,452

)

(3,111

)

(2,201

)

(2,715

)

Net loss applicable to common stockholders

$

(14,278

)

$

(22,768

)

$

(16,764

)

$

(15,674

)

Net loss per sharebasic and diluted

$

(17.80

)

$

(22.93

)

$

(17.83

)

$

(11.87

)

Weighted-average number of common shares used in net loss per sharebasic and diluted

802

993

940

1,320

Pro forma net loss per sharebasic and diluted (unaudited)

$

(2.76

)

$

(1.52

)

Weighted average number of common shares used in pro forma net loss per sharebasic and diluted (unaudited)

7,118

8,539

See Note 2 within the
notes to our financial statements appearing at the end of this prospectus for a description of the method used to calculate basic and diluted net loss per share applicable to common stockholders and unaudited pro forma basic and diluted net loss per
share.

MANAGEMENTS DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
AND RESULTS OF OPERATIONS

You should read
the following discussion and analysis of our financial condition and results of operations together with our financial statements and related notes appearing in this prospectus. Some of the information contained in this discussion and analysis or
set forth elsewhere in this prospectus, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. As a result of many factors,
including those factors set forth in the Risk Factors section of this prospectus, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion
and analysis.

Overview

We are a clinical-stage biopharmaceutical company with a
proprietary protein engineering platform, called AMP-Rx, that we apply to the discovery and development of protein therapeutics to treat diseases of the eye. Our therapeutic approach is based on the role of cytokines in diseases of the eye, our
understanding of the structural biology of cytokines and our ability to rationally design and engineer proteins to modulate the effects of cytokines. Cytokines are cell signaling molecules found in the body that can have important inflammatory
effects. Our most advanced product candidate is EBI-005, which we designed, engineered and generated using our AMP-Rx platform and are developing as a topical treatment for dry eye disease and allergic conjunctivitis. In 2013, we completed a Phase
1b/2a clinical trial of EBI-005 in patients with moderate to severe dry eye disease. We are initiating a pivotal Phase 3 clinical program evaluating EBI-005 for the treatment of moderate to severe dry eye disease. We also plan to initiate a Phase 2
clinical trial to evaluate the use of EBI-005 in patients with allergic conjunctivitis in early 2014. We hold worldwide commercialization rights to EBI-005.

We were incorporated and commenced active operations in early
2008, and our operations to date have been limited to organizing and staffing our company, acquiring rights to intellectual property, business planning, raising capital, developing our technology, identifying potential product candidates,
undertaking preclinical studies and, beginning in 2012, conducting clinical trials. To date, we have financed our operations primarily through private placements of our preferred stock and convertible bridge notes, venture debt borrowings and, to a
lesser extent, from a collaboration. All of our revenue to date has been collaboration revenue, which we first began to generate in 2013. We recognized collaboration revenue of $0.8 million for the nine months ended September 30, 2013. Since
inception, we have incurred significant operating losses. As of September 30, 2013, we had an accumulated deficit of $52.5 million. Our net loss was $12.8 million for the year ended December 31, 2011, $19.7 million for the year ended
December 31, 2012 and $13.0 million for the nine months ended September 30, 2013.

We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we initiate and complete our planned pivotal Phase 3 clinical program for EBI-005, consisting of
two Phase 3 clinical trials evaluating EBI-005 for the treatment of moderate to severe dry eye disease and a separate clinical trial evaluating the safety of treatment with EBI-005 for one year, and seek marketing approval for EBI-005 for this indication in the United States and, whether alone or in collaboration with third parties, in the European Union and other jurisdictions. We also expect our expenses to increase as we initiate and
conduct additional clinical trials of EBI-005 for the treatment of allergic conjunctivitis or additional indications or for use in other patient populations and as we continue research and development and
initiate additional clinical trials of, and seek marketing approval for, our other product candidates. In addition, if we obtain marketing approval for EBI-005 or any other product candidates, we expect to incur significant commercialization
expenses related to product manufacturing, marketing, sales and distribution. Furthermore, upon the closing of this offering, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain
substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or any future
commercialization efforts.

To date, we have not generated any revenues from the sale of
products. All of our revenue to date has been derived from a collaboration. We do not expect to generate significant product revenue unless and until we obtain marketing approval for, and commercialize, EBI-005, which we do not expect will occur
before 2017, if ever.

We have generated
collaboration revenue exclusively from our collaboration and license agreement with ThromboGenics N.V., or Thrombogenics, which we entered into in May 2013. Under the agreement, we and ThromboGenics are collaborating to identify protein or peptide
therapeutics that directly modulate any of a specified set of targets in a novel pathway in retinal disease. We call the therapeutics that are identified, and whose modulation of one of the targets is confirmed, in the course of the research
collaboration, collaboration products. The initial research term extends for 30 months from the date we entered into the agreement, but may be extended on mutual agreement. The agreement expires when all of ThromboGenics payment obligations
expire. We are responsible for specified non-clinical activities during the research term. ThromboGenics is responsible for all development, manufacturing and commercialization activities with respect to the collaboration products. We granted
ThromboGenics an exclusive, sublicensable, worldwide royalty-bearing license under our rights in any intellectual property made in the course of this collaboration, as well as under any other intellectual property we control during the research term
that is necessary for ThromboGenics to perform its obligations to research, develop, manufacture and commercialize collaboration products. During the term of the agreement, neither we nor ThromboGenics, nor our respective affiliates other than any
entities which become affiliates as a result of an acquisition of us or ThromboGenics, are permitted to research, develop, manufacture or commercialize any protein or peptide therapeutic that directly modulates one of the specified targets, except
as otherwise provided in the agreement.

In
connection with the agreement, we received an upfront, non-refundable payment of $1.75 million, and are entitled to receive payment for our performance of activities under the agreement at a set rate per full time annual equivalent personnel for
research services pursuant to the agreement. We identified three deliverables in the arrangement: the research license, the research services and our participation on the joint research committee, or JRC deliverable, and concluded that there are two
units of accounting: a combined research license and research services deliverable and the JRC deliverable. The estimated selling price for the JRC deliverable was de minimis, and thus we allocated the fixed arrangement consideration to the
combined unit of accounting. We are recognizing revenue using the proportional performance method by which the amounts are recognized in proportion to the costs incurred based on full time equivalent efforts. In addition, we are eligible to receive
up to an aggregate of $10.0 million if ThromboGenics achieves specified preclinical and clinical development milestones and up to an aggregate of $15.0 million if ThromboGenics achieves specified regulatory milestones. There are no commercialization
or sales based milestones under the agreement. ThromboGenics is obligated to pay us a low single digit royalty on the sale of collaboration products. We recognized collaboration revenue of $0.8 million in connection with this collaboration for the
nine months ended September 30, 2013. We expect that any revenue we generate from our collaboration with ThromboGenics will fluctuate from quarter to quarter as a result of the uncertain timing and amount of payments for research services,
milestone payments and royalties.

Research and Development
Expenses

Research and development
expenses consist primarily of costs incurred for the development of our product candidates, which include:

facilities, depreciation, and other expenses, which include direct and allocated expenses for rent and maintenance of facilities, insurance, and other
supplies; and



expenses associated with preclinical and regulatory activities.

We expense research and development costs as incurred. We
recognize external development costs based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors and our clinical sites.

In April 2013, we implemented a strategic restructuring designed to conserve resources and improve our
financial position. As part of this strategic restructuring, we reduced spending on early stage research programs and implemented a reduction in force of 15 positions, or 50% of our workforce, primarily in the research area. We expect our research
and development expenses to increase substantially as compared to prior periods in connection with conducting our planned pivotal Phase 3 clinical program for EBI-005, seeking marketing approval for EBI-005 in the United States and, whether alone or
in collaboration with third parties, in the European Union and other jurisdictions, initiating and conducting additional clinical trials of EBI-005 for the treatment of allergic conjunctivitis or additional indications or for use in other patient
populations and continuing the research and development and initiating clinical trials of our other product candidates.

We estimate that we will incur external research and development expenses of approximately $36 million to complete our planned pivotal
Phase 3 clinical program evaluating EBI-005 and to submit a Biologics License Application, or BLA, to the United States Food and Drug Administration, or FDA, seeking approval of EBI-005 for the treatment of dry eye disease in the United States in
the second half of 2016. We estimate that we will incur additional external research and development expenses of approximately $3 million to complete our planned Phase 2 clinical trial evaluating the use of EBI-005 in patients with allergic
conjunctivitis. The remaining net proceeds of this offering will be used to fund our internal research and development expenses for EBI-005, internal and external research and development expenses for our preclinical and research and discovery
programs and for working capital and other general corporate purposes during the period from the completion of this offering until we file our BLA for EBI-005 for the treatment of dry eye disease. At this time, we cannot reasonably estimate the
remaining costs necessary to commercialize EBI-005 for the treatment of dry eye disease, including commercial manufacturing of EBI-005, or the nature, timing or costs of the efforts necessary to complete the development of any other product
candidate.

The successful development and
commercialization of our product candidates is highly uncertain. This is due to the numerous risks and uncertainties associated with product development and commercialization, including the uncertainty of:



the scope, progress, outcome and costs of our clinical trials and other research and development activities;



the efficacy and potential advantages of our product candidates compared to alternative treatments, including any standard of care;

A change in the outcome of any of these variables with
respect to the development of EBI-005 or any other product candidate that we may develop could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the FDA or another regulatory
authority were to require us to conduct clinical trials or other testing beyond those that we currently contemplate will be required

for the completion of clinical development of EBI-005 or any other product candidate that we may develop or if we experience significant delays in enrollment in any of our clinical trials, we
could be required to expend significant additional financial resources and time on the completion of clinical development of that product candidate.

We allocate direct research and development expenses, consisting principally of external costs, such as fees paid to investigators,
consultants, central laboratories and CROs in connection with our clinical trials, and costs related to manufacturing or purchasing clinical trial materials, to specific product programs. We do not allocate employee and contractor-related costs,
costs associated with our platform and facility expenses, including depreciation or other indirect costs, to specific product programs because these costs are deployed across multiple product programs under research and development and, as such, are
separately classified. The table below provides research and development expenses incurred for our EBI-005 product program and other expenses by category. We did not allocate research and development expenses to any other specific product program
during the periods presented:

Year ended December 31,

Nine months ended September 30,

2011

2012

2012

2013

(in thousands)

EBI-005

$

2,627

$8,680

$

6,350

$

5,690

Personnel and other expenses:

Employee and contractor-related expenses

4,009

3,867

2,900

3,292

Platform-related lab expenses

1,746

1,710

1,339

800

Facility expenses

772

733

558

599

Other expenses

257

273

220

195

Total personnel and other expenses

6,784

6,583

5,017

4,886

Total research and development expenses

$

9,411

$

15,263

$

11,367

$

10,576

General and Administrative Expenses

General and administrative expenses
consist primarily of salaries and related costs for personnel, including stock-based compensation, in executive, operational, finance and human resource functions. Other general and administrative expenses include facility-related costs and
professional fees for legal, patent, consulting and accounting services.

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support our continued research and development and potential commercialization of our
product candidates. We also anticipate increased accounting, audit, legal, regulatory, compliance, insurance and investor and public relations expenses associated with being a public company.

Other Income (Expense), Net

Other income and expense consists primarily of interest
income earned on cash and cash equivalents, interest expense on outstanding debt and the gain or loss associated with the change in the fair value of our preferred stock warrant liability and the convertible notes that are carried at fair value.

Critical Accounting Policies and Significant Judgments and
Estimates

This managements discussion
and analysis of our financial condition and results of operations is based on our financial statements, which we have prepared in accordance with U.S. generally accepted accounting principles. The preparation of these financial statements requires
us to make estimates and judgments that affect

the reported amounts of assets, liabilities, and expenses and the disclosure of contingent assets and liabilities in our financial statements. On an ongoing basis, we evaluate our estimates and
judgments, including those related to revenue recognition, accrued research and development expenses and stock-based compensation. We base our estimates on historical experience, known trends and events and various other factors that we believe are
reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under
different assumptions or conditions.

While our
significant accounting policies are described in more detail in the notes to our financial statements appearing at the end of this prospectus, we believe the following accounting policies to be most critical to the judgments and estimates used in
the preparation of our financial statements.

Revenue
Recognition

We recognize revenue in
accordance with Accounting Standards Codification, or ASC, 605, Revenue Recognition. Accordingly, we recognize revenue for each unit of accounting when all of the following criteria are met:



Persuasive evidence of an arrangement exists;



Delivery has occurred or services have been rendered;



The sellers price to the buyer is fixed or determinable; and



Collectability is reasonable assured.

We record as deferred revenue any amounts received prior to satisfying the revenue recognition criteria. We classify as deferred revenue,
current any amounts expected to be recognized as revenue within the 12 months following the balance sheet date. We classify as deferred revenue, net of current portion any amounts not expected to be recognized as revenue within the 12 months
following the balance sheet date.

We evaluate
multiple-element arrangements based on the guidance in ASC Topic 605-25, Revenue Recognition-Multiple-Element Arrangements, or ASC 605-25. Pursuant to the guidance in ASC 605-25, we evaluate multiple-element arrangements to determine
(1) the deliverables included in the arrangement and (2) whether the individual deliverables represent separate units of accounting or whether they must be accounted for as a combined unit of accounting. This evaluation involves subjective
determinations and requires us to make judgments about the individual deliverables and whether such deliverables are separable from the other aspects of the contractual relationship. Deliverables are considered separate units of accounting provided
that the delivered item has value to the customer on a standalone basis, and if the arrangement includes a general right of return with respect to the delivered item, delivery or performance of the undelivered item is considered probable and
substantially in our control. In assessing whether an item has standalone value, we consider factors such as the research, development, manufacturing and commercialization capabilities of the collaboration partner and the availability of the
associated expertise in the general marketplace. In addition, we consider whether the collaboration partner can use any other deliverable for its intended purpose without the receipt of the remaining deliverable, whether the value of the deliverable
is dependent on the undelivered item and whether there are other vendors that can provide the undelivered items. The consideration received under the arrangement that is fixed or determinable is then allocated among the separate units of accounting
using the relative selling price method. We determine the selling price of a unit of accounting following the hierarchy of evidence prescribed by ASC 605-25. Accordingly, we determine the estimated selling price for units of accounting within each
arrangement using vendor-specific objective evidence, or VSOE, of selling price, if available, third-party evidence, or TPE, of selling price if VSOE is not available, or best estimate of selling price, or BESP, if neither VSOE nor TPE is available.

We recognize arrangement consideration allocated
to each unit of accounting when all of the revenue recognition criteria in ASC 605 are satisfied for that particular unit of accounting. In the event that a deliverable

does not represent a separate unit of accounting, we recognize revenue from the combined unit of accounting over our contractual or estimated performance period for the undelivered items, which
is typically the term of our research and development obligations. If there is no discernible pattern of performance or objectively measurable performance measures do not exist, then we recognize revenue under the arrangement on a straight-line
basis over the period we are expected to complete our performance obligations. Conversely, if the pattern of performance in which the service is provided to the customer can be determined and objectively measurable performance measures exist, then
we recognize revenue under the arrangement using the proportional performance method. Revenue recognized is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the
straight-line method or proportional performance method, as applicable, as of the period ending date.

At the inception of an arrangement that includes milestone payments, we evaluate whether each milestone is substantive and at risk to both
parties on the basis of the contingent nature of the milestone. This evaluation includes an assessment of whether: (1) the consideration is commensurate with either our performance to achieve the milestone or the enhancement of the value of the
delivered item as a result of a specific outcome resulting from our performance to achieve the milestone; (2) the consideration relates solely to past performance; and (3) the consideration is reasonable relative to all of the deliverables
and payment terms within the arrangement. We evaluate factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the particular milestone and the level of effort and investment required to
achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. We have concluded that certain
of the preclinical and clinical development milestone payments pursuant to our collaboration and license arrangement with ThromboGenics are substantive. Accordingly, in accordance with ASC Topic 605-28, Revenue Recognition-Milestone Method,
we will recognize revenue in its entirety upon successful accomplishment of these milestones, assuming all other revenue recognition criteria are met. Milestones that are not considered substantive are recognized as earned if there are no remaining
performance obligations or over the remaining period of performance, assuming all other revenue recognition criteria are met.

Accrued Research and Development Expenses

As part of the process of preparing our financial statements, we are required to estimate our accrued expenses. This process involves
reviewing quotes and contracts, identifying services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of
the actual cost. The majority of our service providers invoice us monthly in arrears for services performed or when contractual milestones are met. We make estimates of our accrued expenses as of each balance sheet date in our financial statements
based on facts and circumstances known to us at that time. We periodically confirm the accuracy of our estimates with the service providers and make adjustments if necessary. The significant estimates in our accrued research and development expenses
are related to fees paid to CROs and other vendors in connection with research and development activities for which we have not yet been invoiced.

We base our expenses related to CROs on our estimates of the services received and efforts expended pursuant to quotes and contracts with
CROs that conduct research and development on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our
vendors will exceed the level of services provided and result in a prepayment of the research and development expense. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended
in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or prepayment expense accordingly. Although we do not expect our estimates to be materially different from
amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and could result in our reporting amounts that are too high or too low in any
particular period. There have been no material changes in estimates for the periods presented.

We account for all stock-based compensation payments to
employees, directors and non-employees using an option pricing model for estimating fair value. Accordingly, stock-based compensation expense is measured based on the estimated fair value of the awards on the date of grant, net of estimated
forfeitures. We recognize compensation expense for the portion of the award that is ultimately expected to vest over the period during which the recipient renders the required services to us using the straight-line method. In accordance with
authoritative guidance, we remeasure the fair value of non-employee stock-based awards as the awards vest, and recognize the resulting value, if any, as expense during the period the related services are rendered.

Significant Factors, Assumptions and Methodologies Used
in Determining Fair Value

We apply the
fair value recognition provisions of ASC Topic 718, Compensation-Stock Compensation, or ASC 718. Determining the amount of stock-based compensation to be recorded requires us to develop estimates of the fair value of stock options as of their
grant date. We recognize stock-based compensation expense ratably over the requisite service period, which in most cases is the vesting period of the award. Calculating the fair value of stock-based awards requires that we make highly subjective
assumptions.

We use the Black-Scholes option
pricing model to value our stock option awards. Use of this valuation methodology requires that we make assumptions as to the volatility of our common stock, the expected term of our stock options, the risk free interest rate for a period that
approximates the expected term of our stock options and our expected dividend yield. Because we are a privately held company with a limited operating history, we utilize data from a representative group of public companies to estimate expected stock
price volatility. We selected companies from the biopharmaceutical industry with similar characteristics to us, including those at a similar stage of development and with a similar therapeutic focus.

We use the simplified method to estimate the
expected term of stock option grants to employees. Under this approach, the weighted-average expected life is presumed to be the average of the contractual term (ten years) and the vesting term (generally four years) of our stock options, taking
into consideration multiple vesting tranches. We utilize this method due to lack of historical exercise data and the plain-vanilla nature of our share-based awards. We have never paid, and do not anticipate paying, any cash dividends in the
foreseeable future, and therefore use an expected dividend yield of zero in the option-pricing model. The risk-free rate is based on the yield curve of U.S. Treasury securities with periods commensurate with the expected term of the options being
valued. The fair value of each stock option granted to employees is estimated on the date of grant using the Black-Scholes option-pricing model based on the assumptions noted in the following table:

Year ended December 31,

Nine months endedSeptember 30,

2011

2012

2012

2013

Risk-free interest rate

1.16-2.69

%

0.57-0.95

%

0.57-0.95

%

1.09-1.85

%

Expected dividend yield









Expected term (in years)

6

6

6

6

Expected volatility

70.61

%

70.48-70.80

%

70.48-70.80

%

76.58-77.80

%

We are also required to
estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from our estimates. We use historical data to estimate pre-vesting option forfeitures and record stock-based compensation expense
only for those awards that are expected to vest. To the extent that actual forfeitures differ from our estimates, the difference is recorded as a cumulative adjustment in the period the estimates are revised. Stock-based compensation expense
recognized in the financial statements is based on awards that are ultimately expected to vest. Through September 30, 2013, actual forfeitures have not been material.

Stock-based compensation expense associated with stock options granted to employees and
non-employees was $38,000 for the year ended December 31, 2011, $0.1 million for the year ended December 31, 2012, $0.1 million for the nine months ended September 30, 2012 and $0.8 million for the nine months ended
September 30, 2013. As of September 30, 2013, we had $1.2 million of total unrecognized stock-based compensation expense related to service-based vesting awards, which we expect to recognize over a weighted-average remaining vesting period
of approximately 2.32 years. In addition, as of September 30, 2013, we had unrecognized compensation expense related to performance-based awards of $1.4 million, which will be recorded when the vesting conditions become probable of achievement.
Our stock-based compensation expense is expected to increase as a result of recognizing our existing unrecognized stock-based compensation for awards that will vest and as we issue additional stock-based awards to attract and retain our employees.

For the years ended December 31, 2011 and
2012 and for the nine months ended September 30, 2012 and 2013, we allocated stock-based compensation expense as follows:

Year ended December 31,

Nine months ended September 30,

2011

2012

2012

2013

(in thousands)

Research and development expense

$

37

$

117

$

92

$

715

General and administrative expense

1

13

8

40

Total stock-based compensation expense

$

38

$

130

$

100

$

755

Fair Value of Common
Stock

We are required to estimate the
fair value of our common stock underlying our stock-based awards when performing the fair value calculations using the Black-Scholes option pricing model. The fair value of our common stock underlying our stock-based awards was determined on each
grant date by our board of directors, with input from management. All options to purchase shares of our common stock are intended to be granted with an exercise price per share no less than the fair value per share of our common stock underlying
those options on the date of grant, based on the information known to us on the date of grant. In the absence of a public trading market for our common stock, on each grant date, we develop an estimate of the fair value of our common stock in order
to determine an exercise price for the option grants. We determined the fair value of stock options using methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants, or AICPA, Audit and
Accounting Practice Aid Series: Valuation of Privately Held Company Equity Securities Issued as Compensation, or the AICPA Practice Guide. In addition, we considered various objective and subjective factors, along with input from management and
contemporaneous valuations, to determine the fair value of our common stock, including:



external market conditions affecting the biotechnology industry;



trends within the biotechnology industry;



the prices at which we sold shares of preferred stock;



the superior rights and preferences of the preferred stock relative to our common stock at the time of each grant;



our results of operations and financial position;



the status of our research and development efforts;



our stage of development and business strategy;



the lack of an active public market for our capital stock; and



the likelihood of achieving a liquidity event, such as an initial public offering, or IPO, or sale of our company in light of prevailing market
conditions.

The per share
estimated fair value of common stock in the table below represents the determination by our board of directors of the fair value of our common stock as of the date of grant, taking into consideration the

various objective and subjective factors described above, including the conclusions, if applicable, of contemporaneous valuations of our common stock as discussed below. The following table sets
forth information about our stock option grants since January 1, 2012:

Date of Grant

Number ofsharesunderlyingoptiongrants

Exercisepricepershare

Per shareestimatedfairvalue ofcommonstock

February 16, 2012

23,622

$

0.76

$

0.76

May 17, 2012

103,811

0.76

0.76

August 9, 2012

18,268

0.76

0.76

February 14, 2013

84,646

0.83

0.83

February 22, 2013

173,228

0.83

0.83

March 15, 2013

90,551

0.83

0.83

May 16, 2013

25,197

0.83

0.83

August 15, 2013

92,913

6.22

6.22

October 31, 2013

160,315

7.37

7.37

November 5, 2013

15,748

7.37

7.37

December 19, 2013

145,748

9.59

9.59

December 26, 2013

94,488

9.59

9.59

In determining the
exercise prices of the options set forth in the table above granted since January 1, 2012, our board of directors considered the most recent valuations of our common stock, which were prepared as of November 1, 2011, November 1,
2012, June 30, 2013, August 15, 2013, September 30, 2013 and December 17, 2013 and based its determination in part on the analyses summarized below.

The intrinsic value of all outstanding vested and
unvested options as of September 30, 2013 was $13.2 million based on a per share price of $14.00, the midpoint of the price range set forth on the cover page of this prospectus, 1,009,279 shares of common stock issuable upon the exercise
of options outstanding as of September 30, 2013 and a weighted average exercise price of $0.95 per share.

Valuations

Common stock valuation methodologies. These valuations of our common stock were prepared in accordance with
the guidelines in the AICPA Practice Guide, which prescribes several valuation approaches for determining the value of an enterprise, such as the cost, market and income approaches, and various methodologies for allocating the value of an enterprise
to its capital structure and specifically the common stock.

We generally used the market approach, in particular the guideline company and precedent transaction methodologies, based on inputs from comparable public companies equity valuations and comparable
acquisition transactions, to estimate the equity value of our company. Additionally, if applicable, we considered company valuations implied by arms length transactions involving sale of our securities to independent investors, taking into
consideration the various rights and preferences of the equity securities transacted.

Methods used to allocate our enterprise value to classes of securities. In accordance with the AICPA Practice Guide, we considered the following methods for allocating the
enterprise value across our classes and series of capital stock to determine the fair value of our common stock at each valuation date.



Option pricing method, or OPM. The OPM treats common stock and preferred stock as call options on the enterprises
value, with exercise prices based on the liquidation preference and conversion terms of the preferred stock. Under this method, the common stock has value only if the funds available for

distribution to stockholders exceed the value of the liquidation preference at the time of a liquidity event (for example, merger or sale).



Probability-weighted expected return method, or PWERM. Under a PWERM, the value of the various equity securities are
estimated based upon an analysis of future values for the enterprise assuming various future outcomes. Share value is based upon the probability-weighted present value of expected future investment returns, considering each of the possible future
outcomes available to the enterprise, as well as the rights of each share class.

For each of the valuations described below, we used either the OPM or the PWERM to determine the estimated fair value of our common stock. The method selected was based on availability and the quality of
information to develop the assumptions for the methodology.

Valuation of common stock as of November 1, 2011

We conducted a contemporaneous valuation of our common
stock as of November 1, 2011. In conducting this valuation we estimated the value of our common stock based on the estimated value of our series A preferred stock. Our series A preferred stock financing, or series A financing, was structured to
close in three tranches, each priced at $1.00 per share, or $6.35 per share on a common stock equivalent basis as a result of the reverse stock split of our common stock that became effective on January 21, 2014. As noted in the AICPA Practice
Guide, in a tranched financing, the per-share price paid in the early tranches is assumed to consist of the value of the preferred security and the value of a contingent forward contract to invest in subsequent tranches. After adjusting for the
contingent forward contract, a value of $0.83 per share was assumed for series A preferred stock as of the closing of the second tranche of the series A financing in February 2011, or $5.27 per share on a common stock equivalent basis as a
result of the reverse stock split of our common stock that became effective on January 21, 2014. We concluded that the terms of the series A financing were representative of fair value. We utilized the back-solve method (a form of the market
approach defined in the AICPA Practice Guide) to estimate the equity value at November 1, 2011 that was implied by the arms length series A financing.

In applying the back-solve method, we utilized the OPM. For
the OPM analysis, we estimated a weighted-average time to liquidity of 2.6 years as of November 1, 2011, which was our best estimate for potential exit scenarios for the investors. Annual volatility of 56% was assumed based on an analysis of
guideline public companies historical equity volatility for a period of 2.6 years, which was the term assumption. The risk-free rate assumption was based on the yield on three-year U.S. Treasury bonds as of November 1, 2011. The exercise
prices assumed for the OPM were determined by the features of the series A preferred stock, including a per-share liquidation preference, a price at which preferred participation is capped and a price at which the preferred shares convert to common.
Based on these OPM assumptions, an implied equity value of $18.6 million was determined. At this equity value, the value per share for the series A preferred stock was equal to its per-share issuance price adjusted for the tranched structure of the
series A financing.

Based on these
assumptions, the implied value per share of the common stock on a minority, marketable basis was $0.95. Because our common stock as of November 1, 2011 was not publicly traded or marketable, we applied a discount for lack of marketability of
21% to the calculated value. The discount for lack of marketability was based on a quantitative put option calculation. We concluded that our common stock had a fair value of $0.76 per share as of November 1, 2011.

Stock options granted from January 2012 to August 2012

Our board of directors granted stock
options on February 16, 2012, May 17, 2012, and August 9, 2012, in each case with an exercise price of $0.76 per share, which our board of directors determined to be the fair value of our common stock on each grant date. In
addition to the objective and subjective factors discussed above, our board of directors also considered input from management and the valuation as of November 1, 2011 in estimating the fair value of our common stock. Given the lack of clarity
around a future liquidity event, the lack

of significant progress in our research and development programs and a lack of business development activities in the first eight months of 2012, our board of directors determined that no
significant events or other circumstances had occurred between November 1, 2011 and August 9, 2012 that would indicate there was a change in the fair value of our common stock during that period.

Valuation of common stock as of November 1, 2012

We conducted a contemporaneous valuation
of our common stock as of November 1, 2012. In assessing the fair value of our common stock, we considered the lack of significant progress in our development programs, including the fact that we had not commenced our Phase 1 clinical trial of
EBI-005. In conducting this valuation we estimated the value of our common stock based on the price at which we sold shares of our series A preferred stock. The third tranche of our series A financing had its final closing on April 23, 2012. A
new, independent investor participated in the third tranche and increased the size of this financing. As such, we concluded that the price paid for the series A preferred stock was representative of fair value. We utilized the back-solve method to
estimate the equity value at November 1, 2012 that was implied by this arms length purchase of series A preferred stock.

In applying the back-solve method, we utilized the OPM. For the OPM analysis, we estimated a weighted-average time to liquidity of 3.0
years as of November 1, 2012, which was our best estimate for potential exit scenarios for the investors. Annual volatility of 38% was assumed based on an analysis of guideline public companies historical equity volatility for a period of
3.0 years, which was the term assumption. The risk-free rate assumption was based on the yield on three-year U.S. Treasury bonds as of November 1, 2012. The exercise prices assumed for the OPM were determined by the features of the series A
preferred stock, including a per-share liquidation preference, a price at which preferred participation is capped and a price at which the preferred shares convert to common. Based on these OPM assumptions, an implied equity value of $47.8 million
was determined. At this equity value, the value per-share for the series A preferred stock was equal to the per-share issuance price of $6.35 on a common stock equivalent basis.

Based on these assumptions, the implied value per share of
the common stock on a minority, marketable basis was $0.95. Because our common stock as of November 1, 2012 was not publicly traded or marketable, we applied a discount for lack of marketability of 15% to the calculated value. The discount for
lack of marketability was based on a quantitative put option calculation. Based on these factors, we concluded that our common stock had a fair value of $0.83 per share as of November 1, 2012.

Stock options granted from February 2013 to May 2013

Our board of directors granted stock
options on February 14, 2013, February 22, 2013, March 15, 2013 and May 16, 2013, in each case with an exercise price of $0.83 per share, which our board of directors determined to be the fair value of our common stock
on each grant date. In addition to the objective and subjective factors discussed above, our board of directors also considered input from management and the valuation as of November 1, 2012 in estimating the fair value of our common stock.
Given the lack of clarity around a future liquidity event and the lack of significant clinical data in the first five months of 2013, our board of directors determined that no significant events or other circumstances had occurred between
November 1, 2012 and May 16, 2013 that would indicate there was a change in the fair value of our common stock during that period.

Valuation of common stock as of June 30, 2013

While we did not grant any stock options during the period from May 17, 2013 to June 30, 2013, we did conduct a contemporaneous valuation
at June 30, 2013 for financial reporting purposes that included the measurement of non-employee stock-based compensation expense. In assessing the fair value of our common stock, we considered the fact that EBI-005 had completed a Phase 1b/2a trial
and demonstrated an acceptable safety profile to advance to pivotal trials, which led us to expect an increase in the fair value of our common stock.

Our contemporaneous valuation at June 30, 2013 used the PWERM. We assumed an IPO
scenario, a high case sale/merger scenario and a low case sale/merger scenario. In order to estimate expected proceeds from each potential exit scenario, we considered data from the biopharmaceutical industry for initial public offerings and merger
and acquisition transactions. In addition we also considered the valuation of our last private financing in April 2012. For the IPO scenario, we assumed that all of our preferred shares would convert to common shares. For the high case sale/merger
scenario, we assumed that the IPO would not occur and that we would continue to make significant progress in clinical development. For the low case sale/merger scenario, we assumed that the IPO would not occur and that the future sale price would
reflect a lack of progress in clinical trials, a lack of necessary funding or both.

We discounted the future value associated with each scenario to present value as of June 30, 2013 by applying a discount rate. Given our stage of development at June 30, 2013 and the differences
in risk between our preferred and common shares, we applied a discount rate of 24% to our preferred shares and 28% to our common shares. The discount rates were based on the typical venture capital rates of return for companies in the bridge/IPO
stage of development, as reported in the AICPA Practice Guide. We applied a discount for lack of marketability to the probability-weighted present value of our common stock. The discount for lack of marketability was based on a quantitative put
option calculation.

The following table
summarizes the significant assumptions for each of the valuation scenarios used in the PWERM analysis to determine the fair value of our common stock as of June 30, 2013:

June 30, 2013 valuation assumptions

IPO

Sale-high case

Sale-low case

Probability weighting

15

%

45

%

40

%

Liquidity date

3/31/14

6/30/16

6/30/16

Discount rate, preferred

24

%

24

%

24

%

Discount rate, common

28

%

28

%

28

%

Discount for lack of marketability

18

%

18

%

18

%

Based on the qualitative
factors described above and the results of our contemporaneous valuation analysis, we determined that the fair value of our common stock at June 30, 2013 was $5.14 per share.

Valuation of common stock as of August 15, 2013

In August 2013, our board of directors authorized the management team to assess the feasibility of an IPO in
the second half of 2013. The boards decision was based on favorable conditions in the market for IPOs by biotechnology companies and the boards increasing confidence in the progress of EBI-005 in
clinical development.

We conducted a
contemporaneous valuation of our common stock as of August 15, 2013. In assessing the fair value of our common stock, we considered the following factors that contributed to an expected increase in the fair value of our common stock:



the outcome of our meeting with the FDAs Division of Transplant and Ophthalmology Products in July 2013 to discuss our planned pivotal Phase 3
clinical program; and



the potential for accelerated timing of an IPO due to our assessment of current market conditions.

Our contemporaneous valuation at August 15, 2013 used
the PWERM. We assumed an IPO scenario, a high case sale/merger scenario and a low case sale/merger scenario. In order to estimate expected proceeds from each potential exit scenario, we considered data from the biopharmaceutical industry for initial
public offerings and merger and acquisition transactions. For the IPO scenario, we assumed that all of our preferred shares would convert to common shares. For the high case sale/merger scenario, we assumed that the IPO would not occur and that we
would continue to make significant progress in clinical development. For the low case sale/merger

scenario, we assumed that the IPO would not occur and that the future sale price would reflect a lack of further progress in clinical development, a lack of necessary funding or both.

We discounted the future value associated with each scenario
to present value as of August 15, 2013 by applying a discount rate. Given our stage of development at August 15, 2013 and the differences in risk between our preferred and common shares, we applied a discount rate of 24% to our preferred
shares and 28% to our common shares. The discount rates were based on the typical venture capital rates of return for companies in the bridge/IPO stage of development, as reported in the AICPA Practice Guide. We applied a discount for lack of
marketability of 17% to the probability-weighted present value of our common stock. The discount for lack of marketability was based on a quantitative put option calculation.

The following table summarizes the significant assumptions
for each of the valuation scenarios used in the PWERM analysis to determine the fair value of our common stock as of August 15, 2013:

August 15, 2013 valuation assumptions

IPO

Sale-high case

Sale-low case

Probability weighting

25

%

45

%

30

%

Liquidity date

3/31/14

6/30/16

6/30/16

Discount rate, preferred

24

%

24

%

24

%

Discount rate, common

28

%

28

%

28

%

Discount for lack of marketability

17

%

17

%

17

%

The increase in the
probability weighting to an IPO as compared to the June 30, 2013 valuation was attributable to the potential for accelerated timing of an IPO based upon market conditions and authorization from our board of directors to proceed with assessing the
feasibility of an IPO.

Based on the
qualitative factors described above and the results of our contemporaneous valuation analysis, we concluded that our common stock had a fair value of $6.22 per share as of August 15, 2013.

Stock options granted on August 15, 2013

Our board of directors granted stock options on
August 15, 2013, with an exercise price of $6.22 per share, which our board of directors determined to be the fair value of our common stock on the date of grant. In addition to the objective and subjective factors discussed above, our board of
directors also considered input from management and the contemporaneous valuation of our common stock as of August 15, 2013 in estimating the fair value of our common stock.

Valuation of common stock as of September 30, 2013

We conducted a contemporaneous valuation of our common stock as of September 30, 2013. In assessing the
fair value of our common stock, we considered the following factors:



we selected underwriters for a potential IPO and scheduled an organizational meeting to be held in the first week of October 2013; and



we completed our first commercial-scale manufacture of the EBI-005 protein for our first planned Phase 3 trial.

Our contemporaneous valuation at September 30, 2013 used
the PWERM. We assumed an IPO scenario, a high case sale/merger scenario and a low case sale/merger scenario. In order to estimate expected proceeds from each potential exit scenario, we considered data from the biopharmaceutical industry for initial
public offerings and merger and acquisition transactions. For the IPO scenario, we assumed that all of our preferred shares would convert to common shares. For the high case sale/merger scenario, we assumed that the IPO would not occur and that we
would continue to make significant progress in clinical development. For the low case sale/merger

scenario, we assumed that the IPO would not occur and that the future sale price would reflect a lack of further progress in clinical development, a lack of necessary funding or both.

We discounted the future value associated with each scenario
to present value as of September 30, 2013 by applying a discount rate. Given our stage of development at September 30, 2013 and the differences in risk between our preferred and common shares, we applied a discount rate of 24% to our
preferred shares and 28% to our common shares. The discount rates were based on the typical venture capital rates of return for companies in the bridge/IPO stage of development, as reported in the AICPA Practice Guide. We applied a discount for lack
of marketability of 14% to the probability-weighted present value of the common stock. The discount for lack of marketability was based on a quantitative put option calculation.

The following table summarizes the significant assumptions
for each of the valuation scenarios used in the PWERM analysis to determine the fair value of our common stock as of September 30, 2013:

September 30, 2013 valuation assumptions

IPO

Sale-high case

Sale-low case

Probability weighting

50

%

30

%

20

%

Liquidity date

1/31/14

6/30/16

6/30/16

Discount rate, preferred

24

%

24

%

24

%

Discount rate, common

28

%

28

%

28

%

Discount for lack of marketability

14

%

14

%

14

%

The increase in the
probability weighting to an IPO as compared to the August 15, 2013 valuation was attributable to our selection of underwriters for a potential IPO and scheduling of an organizational meeting to be held in the first week of October 2013.

Based on the qualitative factors described above and the
results of our contemporaneous valuation analysis, we determined that the fair value of our common stock at September 30, 2013 was $7.37 per share.

Stock options granted on October 31, 2013 and November 5, 2013

Our board of directors granted stock options on
October 31, 2013 and November 5, 2013, in each case with an exercise price of $7.37 per share, which our board of directors determined to be the fair value of our common stock on the date of grant. In addition to the objective and subjective
factors discussed above, our board of directors also considered input from management and the contemporaneous valuation of our common stock as of September 30, 2013 in estimating the fair value of our common stock. After considering this input
and our contemporaneous valuation, our board of directors determined that no significant events or other circumstances had occurred between September 30, 2013 and November 5, 2013 that would indicate there was a change in the fair value of our
common stock during that period.

Valuation of common
stock as of December 17, 2013

We
conducted a contemporaneous valuation of our common stock as of December 17, 2013. In assessing the fair value of our common stock, we considered the following factors:



we confidentially submitted a draft registration statement on November 7, 2013 for a potential IPO;



we confidentially submitted an amendment to our draft registration statement on December 9, 2013; and



we completed our series B preferred stock financing in December 2013 in which we issued and sold an aggregate of 7,203,845 shares of our series B
preferred stock and warrants to purchase 202,472 shares of our common stock for an aggregate purchase price of $12.6 million, consisting of $9.0 million in cash and $3.6 million for the conversion of outstanding convertible promissory notes,
including accrued interest.

Our contemporaneous valuation at December 17, 2013 used the PWERM. We assumed an IPO
scenario, a high case sale/merger scenario and a low case sale/merger scenario. In order to estimate expected proceeds from each potential exit scenario, we considered data from the biopharmaceutical industry for initial public offerings and merger
and acquisition transactions. For the IPO scenario, we assumed that all of our preferred shares would convert to common shares. For the high case sale/merger scenario, we assumed that the IPO would not occur and that we would continue to make
significant progress in clinical development. For the low case sale/merger scenario, we assumed that the IPO would not occur and that the future sale price would reflect a lack of further progress in clinical development, a lack of necessary funding
or both.

We discounted the future value
associated with each scenario to present value as of December 17, 2013 by applying a discount rate. Given our stage of development at December 17, 2013 and the differences in risk between our preferred and common shares, we applied a discount rate
of 24% to our preferred shares and 28% to our common shares. The discount rates were based on the typical venture capital rates of return for companies in the bridge/IPO stage of development, as reported in the AICPA Practice Guide. We applied a
discount for lack of marketability of 9% to the probability-weighted present value of the common stock. The discount for lack of marketability was based on a quantitative put option calculation.

The following table summarizes the significant assumptions
for each of the valuation scenarios used in the PWERM analysis to determine the fair value of our common stock as of December 17, 2013:

December 17, 2013 valuation assumptions

IPO

Sale-high case

Sale-low case

Probability weighting

70

%

20

%

10

%

Liquidity date

2/15/14

6/30/16

6/30/16

Discount rate, preferred

24

%

24

%

24

%

Discount rate, common

28

%

28

%

28

%

Discount for lack of marketability

9

%

9

%

9

%

The increase in the
probability weighting to an IPO as compared to the September 30, 2013 valuation was attributable to our confidential submission of a draft registration statement on November 7, 2013 for a potential IPO and the confidential submission of an amendment
to our draft registration statement on December 9, 2013.

Based on the qualitative factors described above and the results of our contemporaneous valuation analysis, we determined that the fair value of our common stock at December 17, 2013 was $9.59 per share.

Stock options granted on December 19, 2013 and
December 26, 2013

Our board of
directors granted stock options on December 19, 2013 and December 26, 2013, in each case with an exercise price of $9.59 per share, which our board of directors determined to be the fair value of our common stock on the date of grant. In addition to
the objective and subjective factors discussed above, our board of directors also considered input from management and the contemporaneous valuation of our common stock as of December 17, 2013 in estimating the fair value of our common stock. After
considering this input and our contemporaneous valuation, our board of directors determined that no significant events or other circumstances had occurred between December 17, 2013 and December 26, 2013 that would indicate there was a change in the
fair value of our common stock during that period.

On January 21, 2014, we and our underwriters determined the estimated price range for this offering, as set forth on the cover page of
this prospectus. The midpoint of the price range is $14.00 per share. In comparison, on December 26, 2013, we granted options with an exercise price of $9.59 per share, which was our estimate of the fair value of our common stock as of such date. We
note that, as is typical in IPOs, the estimated price range for this offering was not derived using a formal determination of fair value, but was determined by negotiation between us and the underwriters. Among the factors that were considered in
setting this range were our results of operations, current financial condition and markets, the economic conditions in and future prospects for the

industry in which we compete, our management and currently prevailing general conditions in the equity securities markets, including current market valuations of publicly traded companies
considered comparable to us. In addition, at the time these option awards were made, our underwriters had not yet communicated to us their recommendation for the definitive proposed price range for this offering. Specifically, we believe that the
difference between the fair value of our common stock as of December 26, 2013 and the midpoint of the estimated price range for this offering is primarily the result of the following factors:



The estimated price range for this offering necessarily assumes that the IPO has occurred, a public market for our common stock has been created and
that our preferred stock converted into common stock in connection with the IPO, and therefore excludes any discount for lack of marketability of our common stock.



Our preferred stock currently has substantial economic rights and preferences over our common stock. Upon the closing of this offering, all outstanding
shares of our preferred stock will convert into common stock, thus eliminating the superior rights and preferences of our preferred stock as compared to our common stock.



We have begun screening patients for our first Phase 3 clinical trial evaluating EBI-005 for the treatment of moderate to severe dry eye disease and
expect to begin randomizing and treating patients in this trial by early February 2014.



The proceeds of a successful IPO would substantially strengthen our balance sheet by increasing our cash resources. In addition, the completion of this
offering would provide us with readier access to the public company debt and equity markets.

These projected improvements in our financial position influenced the increased common stock valuation indicated by the midpoint of the
estimated price range set forth on the cover page of this prospectus.

Emerging Growth Company Status

The Jumpstart our Business Startups Act of 2012, or the JOBS Act, permits an emerging growth company such as us to take advantage of an extended transition period to comply with new or revised
accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have irrevocably elected to opt out of this provision and, as a result, we will comply with new or revised
accounting standards as required when they are adopted.

Results of Operations

Comparison of the Nine Months Ended September 30, 2012 and 2013

Nine months endedSeptember
30,

2012

2013

Change

(in thousands)

Collaboration revenue

$



$

824

$

824

Operating expenses:

Research and development

11,367

10,576

(791

)

General and administrative

3,081

2,606

(475

)

Total operating expenses

14,448

13,182

(1,266

)

Loss from operations

(14,448

)

(12,358

)

2,090

Other income (expense), net

(115

)

(601

)

(486

)

Net loss

$

(14,563

)

$

(12,959

)

$

1,604

Revenue. Revenue was $0.8 million for the nine months ended September 30, 2013 compared to $0
for the nine months ended September 30, 2012. The increase of $0.8 million was due to revenue recognized pursuant to the ThromboGenics collaboration and license agreement entered into in May 2013.

Research and development expenses. Research and
development expenses were $10.6 million for the nine months ended September 30, 2013 compared to $11.4 million for the nine months ended September 30, 2012. The decrease of $0.8 million was primarily due to a decrease of $0.7 million of
EBI-005 related development expenses and a decrease in platform-related laboratory expenses of $0.5 million. In April 2013, we implemented a strategic restructuring to focus more of our research and development expenses on the development of
EBI-005. As a result, we reduced headcount from 30 to 15, including 13 positions in our research and development function. These decreases in research and development expenses were partially offset by an increase in contractor-related expenses of
$0.4 million to support the increased development activities of the Phase 1b/2a clinical trial of EBI-005.

General and administrative expenses. General and administrative expenses were $2.6 million for the
nine months ended September 30, 2013 compared to $3.1 million for the nine months ended September 30, 2012. The decrease of $0.5 million was primarily due to our strategic restructuring, which focused more of our resources on the
development of EBI-005. As a result of the restructuring in April 2013, we reduced total headcount from 30 to 15, including two positions in our general and administrative function.

Other income (expense), net. Other income (expense), net was $(0.6)
million for the nine months ended September 30, 2013 compared to $(0.1) million for the nine months ended September 30, 2012. The increase was primarily due to the change in the fair value of the warrant liability, which increased from
$0.1 million to $0.2 million, the change in the fair value of convertible notes payable of $0.2 million, and an increase in interest expense due to additional borrowings under our debt facility during the nine months ended September 30,
2013.

Comparison of the Years Ended December 31,
2011 and 2012

Year endedDecember 31,

2011

2012

Change

(in thousands)

Operating expenses:

Research and development

$

9,411

$

15,263

$

5,852

General and administrative

3,267

4,213

946

Total operating expenses

12,678

19,476

6,798

Loss from operations

(12,678

)

(19,476

)

(6,798

)

Other income (expense), net

(148

)

(181

)

(33

)

Net loss

$

(12,826

)

$

(19,657

)

$

(6,831

)

Revenue. We did not recognize any revenue during the years ended December 31, 2011 and 2012.

Research and development
expenses. Research and development expenses were $15.3 million for the year ended December 31, 2012 compared to $9.4 million for the year ended December 31, 2011. The increase of $5.9 million was primarily
due to an increase in costs associated with EBI-005, including clinical supply manufacturing and drug product process development activities in preparation for initiating our Phase 1b/2a trial of EBI-005.

General and administrative
expenses. General and administrative expenses were $4.2 million for the year ended December 31, 2012 compared to $3.3 million for the year ended December 31, 2011. The increase of $0.9 million was
primarily due to an increase in employee and contractor related expenses in support of our development efforts.

Other income (expense), net. Other income (expense), net, was $(0.2) million for the year ended
December 31, 2012 compared to $(0.1) million for the year ended December 31, 2011.

Since inception, we have incurred significant operating
losses. All of our revenue to date has been collaboration revenue. To date, we have financed our operations primarily through private placements of our preferred stock and bridge notes convertible into our preferred stock, venture debt borrowings
and, to a lesser extent, from a collaboration.

In
May 2013, we entered into the collaboration and license agreement with ThromboGenics. Under this collaboration, ThromboGenics made a $1.75 million up-front, non-refundable cash payment to us and will fund the research services that we provide under
the agreement.

In June 2013, we issued and
sold 7% convertible promissory notes in the aggregate principal amount of $3.5 million and accompanying warrants to purchase shares of our common stock to four of the holders of our series A preferred stock. The warrants are initially
exercisable at a price of $0.06 per share for an aggregate of 275,589 shares of our common stock and will expire, to the extent not exercised, upon the closing of this offering. We refer to these convertible promissory notes as the June 2013
convertible notes.

In December 2013, we issued
and sold an aggregate of 7,203,845 shares of our series B preferred stock and accompanying warrants to purchase shares of our common stock to four of the holders of our series A preferred stock and one additional investor, at a price per share of
$1.75, for an aggregate purchase price of $12.6 million, consisting of $9.0 million in cash and $3.6 million for the conversion of the June 2013 convertible notes, including accrued interest. The warrants are initially exercisable at a price of
$0.06 per share for an aggregate of 202,472 shares of our common stock and will expire, to the extent not exercised, upon the closing of this offering.

Cash Flows

As of September 30, 2013, we had cash and cash equivalents of $3.9 million. Cash in excess of immediate requirements is invested in
accordance with our investment policy, primarily with a view to liquidity and capital preservation.

The following table sets forth the primary sources and uses of cash for each of the periods set forth below:

Year endedDecember 31,

Nine months endedSeptember 30,

2011

2012

2012

2013

(in thousands)

Net cash provided by (used in):

Operating activities

$

(10,869

)

$

(19,092

)

$

(14,235

)

$

(10,437

)

Investing activities

(805

)

(110

)

(110

)



Financing activities

10,448

26,384

26,414

6,436

Net (decrease) increase in cash and cash equivalents

$

(1,226

)

$

7,182

$

12,069

$

(4,001

)

Operating
activities. Net cash used in operating activities was $10.9 million for the year ended December 31, 2011, and consisted primarily of a net loss of $12.8 million adjusted for non-cash items, including depreciation expense of $0.4 million
and a net change in operating assets and liabilities of $1.5 million. The significant items in the change in operating assets and liabilities include decreases in other receivables of $0.8 million and increases in accounts payable and accrued
expenses of $0.9 million offset by an increase in prepaid expenses and other current assets of $0.2 million.

Net cash used in operating activities was $19.1 million for the year ended December 31, 2012, and consisted primarily of a net loss
of $19.7 million adjusted for non-cash items, including depreciation expense of $0.4

million, stock-based compensation expense of $0.1 million and a net change in operating assets and liabilities of $(0.1) million.

Net cash used in operating activities was $14.2 million for the nine months ended September 30, 2012, and
consisted primarily of a net loss of $14.6 million adjusted for non-cash items, including depreciation expense of $0.3 million, stock-based compensation expense of $0.1 million and a net change in operating assets and liabilities of $(0.1) million.
The significant items in the change in operating assets and liabilities include a net decrease in accounts payable and accrued expenses of $0.3 million partially offset by a decrease in prepaid expenses and other current assets of $0.2 million.

Net cash used in operating activities was $10.4
million for the nine months ended September 30, 2013, and consisted primarily of a net loss of $13.0 million adjusted for non-cash items, including stock-based compensation expense of $0.8 million, depreciation expense of $0.3 million, change
in fair value of warrant liability of $0.1 million, change in fair value of convertible notes payable of $0.2 million and a net change in operating assets and liabilities of $1.1 million. The significant items in the change in operating assets
and liabilities include an increase in deferred revenue of $1.7 million due to the up-front payment related to the ThromboGenics collaboration partially offset by a decrease in accounts payable and accrued expenses of $0.6 million.

Investing
activities. Net cash used in investing activities consists of purchases of property and equipment. For the years ended December 31, 2011 and 2012, we purchased $0.8 million and $0.1 million, respectively, of
property and equipment, primarily laboratory equipment.

For the nine months ended September 30, 2012, we purchased $0.1 million of property and equipment. We made no such purchases in the nine months ended September 30, 2013.

Financing
activities. Net cash provided by financing activities for the year ended December 31, 2011 was $10.4 million and consisted primarily of proceeds of $11.0 million from the issuance of series A preferred stock
offset by $0.6 million in payments on equipment financing and notes payable. Net cash provided by financing activities for the year ended December 31, 2012 was $26.4 million and consisted primarily of proceeds of $25.4 million from the issuance
of series A preferred stock and additional borrowings under our debt facility of $2.0 million offset by $1.0 million in payments on equipment financing and notes payable.

Net cash provided by financing activities for the nine months
ended September 30, 2012 was $26.4 million and consisted primarily of proceeds of $25.4 million from the issuance of series A preferred stock and additional borrowings under our debt facility of $2.0 million, offset by payments of
$1.0 million on our debt facility. Net cash provided by financing activities for the nine months ended September 30, 2013 was $6.4 million and consisted primarily of proceeds from the issuance of convertible notes of $3.5 million to certain of
our stockholders and additional borrowings under our debt facility of $3.0 million.

Funding Requirements

We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we initiate and complete our planned pivotal Phase 3 clinical program evaluating EBI-005 for the
treatment of moderate to severe dry eye disease, and seek marketing approval for EBI-005 for this indication in the United States and, whether alone or in collaboration with third parties, in the European
Union and other jurisdictions. Furthermore, upon the closing of this offering, we expect to incur additional costs associated with operating as a public company.

Our expenses will also increase if and as we:



pursue the development of EBI-005 for the treatment of allergic conjunctivitis or additional indications or for use in other patient populations or, if
it is approved, seek to broaden the label for EBI-005;

expand our operational, financial and management systems and personnel, including personnel to support our clinical development, manufacturing and
planned future commercialization efforts and our operations as a public company; and

As of September 30, 2013,
we had cash and cash equivalents of $3.9 million. We believe that the net proceeds from this offering, together with our cash and cash equivalents as of September 30, 2013 and the $9.0 million in cash proceeds from our series B preferred
stock financing that we completed in December 2013, will enable us to fund our operating expenses, debt service obligations and capital expenditure requirements into the second half of 2016, without giving effect to any potential milestone payments
we may receive under our collaboration and license agreement with ThromboGenics. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect.

Our future capital requirements will depend on many factors,
including:



the progress, costs and outcome of our planned pivotal Phase 3 clinical program for EBI-005 and of any clinical activities for regulatory review of
EBI-005 outside of the United States;



the costs and timing of process development and manufacturing scale up and validation activities associated with EBI-005;



the costs, timing and outcome of regulatory review of EBI-005 in the United States, the European Union and in other jurisdictions;



the costs and timing of commercialization activities for EBI-005 if we receive, or expect to receive, marketing approval, including the costs and
timing of establishing product sales, marketing, distribution and outsourced manufacturing capabilities;



subject to receipt of marketing approval, revenue received from commercial sales of EBI-005;



the progress, costs and outcome of developing EBI-005 for the treatment of additional indications or for use in other patient populations, including
our planned Phase 2 clinical trial to assess the potential therapeutic benefit of EBI-005 for the treatment of allergic conjunctivitis in patients who do not respond adequately to antihistamines;

the costs and timing of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending
any intellectual property-related claims; and



the extent to which we in-license or acquire rights to other products, product candidates or technologies for the treatment of ophthalmic diseases.

Until such time, if ever, as we
can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, government or other third-party funding, collaborations, strategic alliances, licensing arrangements and
marketing and distribution arrangements. We do not have any committed external source of funds other than research funding under our collaboration and license agreement with ThromboGenics. To the extent that we raise additional capital through the
sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect your rights as a common stockholder. Debt financing and
preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Our pledge
of specified assets as collateral to secure our obligations under our loan and security agreement with our venture debt lender, Silicon Valley Bank, may limit our ability to obtain debt financing. If we raise additional funds through government or
other third-party funding, collaborations, strategic alliances, licensing arrangements or marketing and distribution arrangements, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product
candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or
future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Contractual Obligations and Commitments

The following table summarizes our contractual obligations
at December 31, 2012:

Total

Less than1 year

1 to 3years

3 to 5years

More than5 years

(in thousands)

Operating lease obligations(1)

$

797

$

797

$



$



$



Debt obligations(2)

2,347

282

1,473

592



Total fixed contractual obligations

$

3,144

$

1,079

$

1,473

$

592

$



(1)

We lease office space at 215 First Street in Cambridge, Massachusetts under a non-cancelable operating lease that was scheduled to expire on November 30, 2013.
Effective November 30, 2013, we amended the lease to extend the term through January 31, 2016, with an option to further extend the lease term through April 30, 2018. Rental payments due under this lease from December 1, 2013 through January 31,
2016 will be $0.9 million in total.

(2)

Amounts include payments for interest on our debt obligations.

In May 2010, we entered into a $1.5 million secured debt facility with Silicon Valley Bank. We borrowed an aggregate of $1.5 million under
the debt facility in June and July 2010 and issued Silicon Valley Bank promissory notes. In September 2012, we modified the terms of our secured debt facility with Silicon Valley Bank to increase the amount we could borrow thereunder to $5.0
million. We borrowed $2.0 million under the debt facility in September 2012 and an additional $3.0 million under the debt facility in February 2013. The debt facility is secured by substantially all of our assets except for our intellectual
property. The debt facility carries a fixed interest rate of 5.75%. In addition, on the date that the debt facility is paid in full we are required to make a payment in an amount equal to 4% of total borrowings during the term of the debt facility.
As of December 31, 2012, the outstanding principal balance on the notes was $2.0 million. The debt facility provides for the repayment of the outstanding principal balance in equal monthly amounts beginning in October 2013 through September 2016.
The debt facility contains negative covenants restricting our activities, including limitations on

dispositions, mergers or acquisitions, incurring indebtedness or liens, paying dividends or making investments and certain other business transactions. There are no financial covenants associated
with the debt facility. The obligations under the debt facility are subject to acceleration upon the occurrence of specified events of default, including a material adverse change in our business, operations or financial or other condition.

We also have obligations to pay royalties and to
make future payments to third parties that become due and payable on the achievement of specified development, regulatory and commercial milestones. We have not included these commitments on our balance sheet or in the table above because the
achievement and timing of these contingent payments are not fixed and determinable. These commitments include potential milestone and royalty payments we may be required to make under our license agreement with The Schepens Eye Research Institute,
Inc., or Schepens, under which we obtained an exclusive worldwide license under specified patents and technology owned or controlled by Schepens to research, develop, make, have made, use, sell, offer for sale and import products for the treatment
of inflammation of the eye and adjoining tissues, or anti-IL-1 products, including EBI-005. See BusinessLicense and Collaboration Agreements for additional information regarding our agreement
with Schepens.

We enter into contracts in the
normal course of business with CROs to assist in the performance of our research and development activities and other services and products for operating purposes. These contracts generally provide for termination on notice, and therefore are
cancelable contracts and not included in the table of contractual obligations and commitments.

Net Operating Loss Carryforwards

As of December 31, 2012, we had $37.9 million of federal net operating loss carryforwards, state net operating loss carryforwards of $37.4 million and aggregate federal and state research and
development tax credit carryforwards of $0.9 million available to reduce future taxable income. Due to our history of losses and lack of other positive evidence, we have determined that it is more likely than not that our deferred tax assets will
not be realized, and therefore, the deferred tax assets were fully reduce by a valuation allowance. These federal and state net operating loss carryforwards and federal and state tax credit carryforwards will begin to expire at various dates
beginning in 2014, if not utilized. Utilization of the net operating losses and general business tax credits carryforwards may be subject to a substantial limitation under Sections 382 and 383 of the Internal Revenue Code of 1986 as amended, which
we refer to as the Code, due to changes in ownership of our company that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating losses and general business tax credits carryforwards
that can be utilized annually to reduce future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382 of the Code, results from transactions increasing the ownership of 5-percent
Shareholders (as defined in the Code) in the stock of a corporation by more than 50 percentage points over a three-year period. We have not completed a study to determine the impact of this ownership change on our net operating loss, or NOL,
carryforwards under Section 382 of the Code. If we experience a Section 382 ownership change in connection with this offering or as a result of future changes in our stock ownership, some of which changes are outside our control, the tax
benefits related to the NOL carryforwards may be further limited or lost.

Off-balance Sheet Arrangements

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the Securities and Exchange Commission.

Quantitative and Qualitative Disclosures About Market Risks

We are exposed to market risk related to
changes in interest rates. As of September 30, 2013, we had cash and cash equivalents of $3.9 million, primarily money market mutual funds consisting of U.S. government-backed securities. Our primary exposure to market risk is interest rate
sensitivity, which is affected by changes in

the general level of U.S. interest rates, particularly because our investments are in short-term securities. Our available for sale securities are subject to interest rate risk and will fall in
value if market interest rates increase. Due to the short-term duration of our investment portfolio and the low risk profile of our investments, an immediate 100 basis point change in interest rates would not have a material effect on the fair
market value of our portfolio.

We are a clinical-stage biopharmaceutical company with a proprietary protein engineering platform, called
AMP-Rx, that we apply to the discovery and development of protein therapeutics to treat diseases of the eye. Our therapeutic approach is based on the role of cytokines in diseases of the eye, our understanding of the structural biology of cytokines
and our ability to rationally design and engineer proteins to modulate the effects of cytokines. Cytokines are cell signaling molecules found in the body that can have important inflammatory effects. Our most advanced product candidate is EBI-005,
which we designed, engineered and generated using our AMP-Rx platform and are developing as a topical treatment for dry eye disease and allergic conjunctivitis. In 2013, we completed a Phase 1b/2a clinical trial of EBI-005 in patients with moderate
to severe dry eye disease. We are initiating a pivotal Phase 3 clinical program evaluating EBI-005 for the treatment of moderate to severe dry eye disease. We also plan to initiate a Phase 2 clinical trial to evaluate the use of EBI-005 in patients
with allergic conjunctivitis in early 2014. We hold worldwide commercialization rights to EBI-005.

We believe cytokines play a major role in the pathology underlying many eye diseases and that protein therapeutics are an effective means
of modulating the effects of cytokines in diseases of the eye. We have used our AMP-Rx platform to rationally design, engineer and generate a pipeline of innovative protein therapeutic candidates that target cytokines we believe are central to
diseases of the eye. We are conducting research and development programs directed at both diseases of the front of the eye, such as dry eye disease and allergic conjunctivitis, and diseases of the back of the eye, such as diabetic macular edema, or
DME, and uveitis. Our EBI-005 program is based on the role that elevated levels of the inflammatory cytokine interleukin-1, or IL-1, play in the initiation and maintenance of the inflammation and pain associated with dry eye disease and the redness
and itching associated with allergic conjunctivitis. We also are conducting additional discovery efforts for the treatment of diseases of the back of the eye based on the role that other cytokines play in these diseases.

Dry eye disease affects the ocular surface and is
characterized by symptoms of dryness, pain, discomfort and irritation. If dry eye disease is left untreated or becomes severe, patients may suffer chronic ocular pain and distortion of vision that can significantly reduce their quality of life. Dry
eye disease is one of the leading causes of patient visits to eye care professionals in the United States. According to Market Scope, LLC, or Market Scope, a publisher of research and analysis on the ophthalmic market, approximately 68 million
people in the United States, European Union, Japan and other developed markets have dry eye disease, including approximately 26 million people who suffer from the moderate to severe form of dry eye disease. According to Market Scope, approximately
19 million people in the United States have dry eye disease, including approximately seven million people who suffer from the moderate to severe form of dry eye disease.

The current standard of care for moderate to severe dry eye
disease includes artificial tears and topical anti-inflammatory and immune-modulating drugs. The anti-inflammatory and immune-modulating drug market for the treatment of moderate to severe dry eye disease consists primarily of Restasis, which is
approved for use in the United States, and off-label use of corticosteroids. Restasis is a topically applied, ophthalmic formulation of the immune-modulating drug cyclosporine. Restasis is not approved for the treatment of the symptoms of dry eye
disease, but only for increasing tear production in patients whose tear production is presumed to be suppressed due to ocular inflammation associated with dry eye disease. In clinical trials, approximately 17% of patients reported ocular burning
following the use of Restasis. We believe that there remains a significant unmet medical need for new treatments for patients suffering from moderate to severe dry eye disease.

We designed our Phase 1b/2a clinical trial of EBI-005 principally to assess safety in
dry eye disease patients and secondarily, to measure efficacy in order to inform the design of our planned Phase 3 clinical trials. In our Phase 1b/2a trial, EBI-005 was generally well tolerated. While we did not power our Phase 1b/2a trial to
measure efficacy with statistical significance, and the differences from baseline that we observed in the EBI-005 treatment groups were not statistically significant when compared to differences from baseline in patients who received vehicle
control, we observed the following in this trial:



on the primary efficacy endpoint of change in patient symptoms as assessed by a patient questionnaire called the ocular surface disease index, or OSDI,
an improvement in patients treated with EBI-005 from baseline at six weeks;



on the secondary efficacy endpoint of change in total corneal fluorescein staining, or CFS, a measure of ocular surface injury, an improvement in
patients treated with EBI-005 from baseline at six weeks;



on the painful or sore eyes question of the OSDI, a greater improvement from baseline at six weeks in patients treated with EBI-005 compared to
improvement from baseline at six weeks in patients in the vehicle control group; and



fewer artificial tears used by patients treated with EBI-005 compared with patients in the vehicle control group, and this difference was statistically
significant.

Our planned
pivotal Phase 3 clinical program will consist of two Phase 3 clinical trials evaluating the safety and efficacy of EBI-005 for the treatment of moderate to severe dry eye disease and a separate clinical trial evaluating the safety of treatment with
EBI-005 for one year. We have begun screening patients for our first Phase 3 trial and expect to begin randomizing and treating patients in this trial by early February 2014. Based on our estimates regarding patient enrollment, we expect to have
top-line data from our first Phase 3 trial available in early 2015. We also expect to initiate our separate safety trial in 2014. We currently intend to initiate our second Phase 3 trial after reviewing top-line data from our first Phase 3 trial,
although we may later decide to initiate our second Phase 3 trial while our first Phase 3 trial is ongoing. If the results of both of our Phase 3 trials and our separate safety trial are favorable, we plan to submit a Biologics License Application,
or BLA, to the U.S. Food and Drug Administration, or FDA, seeking approval of EBI-005 for the treatment of dry eye disease in the United States in the second half of 2016.

In addition to our clinical development of EBI-005 in dry eye
disease, in early 2014 we plan to initiate a Phase 2 clinical trial of EBI-005 in patients with allergic conjunctivitis who have not responded adequately to antihistamines and mast cell stabilizers, drugs that inhibit the release of histamine by
cells of the immune system. Allergic conjunctivitis is an inflammatory disease of the conjunctiva, the membrane covering the inside of the eyelids and white part of the eye, primarily from a reaction to allergy-causing substances such as pollen or
pet dander. Our preclinical product candidates include EBI-029 for the treatment of DME, a serious disease of the central portion of the retina known as the macula, and EBI-028 for the treatment of uveitis, which is an inflammatory disease of the
middle layer of the eye known as the uvea.

Background

Until recently, ocular therapies generally
have been developed based on a limited understanding of the biology underlying the initiation and maintenance of the disease state. As a result, many of the therapies for diseases of the eye were not the result of rational drug design, but instead
were ophthalmic formulations of pharmaceuticals, that were originally developed and approved for non-ocular diseases, such as steroids and antihistamines. We believe this limited understanding of the biology of eye diseases impeded the discovery and
development of innovative ophthalmic therapeutics.

Over the past 15 years, researchers have been developing a greater understanding of the key proteins and pathways involved in ocular
disease. For instance, the understanding of the protein pathways involved in the retinal disease wet age-related macular degeneration, or wet AMD, has greatly expanded. Wet AMD is characterized by abnormal new blood vessel growth in the back of the
eye. By studying the biological processes associated with this abnormal growth, researchers identified the key role that a protein called vascular endothelial

growth factor, or VEGF, plays in the initiation and maintenance of wet AMD. This understanding then led to the successful development of VEGF-blockers, such as Lucentis and Eylea, as new
treatments for wet AMD that have dramatically improved outcomes for many patients. The developers of these VEGF-blockers have created a multi-billion dollar ophthalmic drug market where none existed 10 years ago. We believe that we can apply similar
advances in the understanding of other protein pathways involved in eye diseases to the discovery and development of new treatments for these diseases.

Our Approach

We apply a rational, biology-based approach to the discovery and development of novel protein therapeutics for patients suffering from eye
diseases. Our therapeutic approach is based on the role of cytokines in diseases of the eye, our understanding of the structural biology of cytokines and our ability to rationally design and engineer proteins to modulate the effects of cytokines.

AMP-Rx is our proprietary platform that we use to
design, engineer and generate novel protein therapies that modulate key molecular targets we believe are responsible for the initiation or maintenance of an ocular disease. We begin by analyzing the target and identifying the protein-based
approaches we may use to modulate the target. We then generate protein candidates and model protein/target interactions to inform an iterative protein optimization technique. We use this process to modify protein drugs to meet design specifications
for improved biological and drug-like properties. We believe that key advantages of the AMP-Rx platform are:

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Broad applicability. We can apply the AMP-Rx platform to select among most forms of protein therapeutics, including
antibodies, enzymes, soluble receptors and signaling proteins, for the optimal approach to treatment.

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Efficiency. We use the AMP-Rx platform to optimize multiple properties of drug candidates simultaneously. We generally
avoid the time-consuming approach of traditional protein drug discovery that involves sequential screening and selection of product characteristics.

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Customized drug design. We use the AMP-Rx platform to design and engineer therapeutics that incorporate a range of key
pharmaceutical properties, such as rapid onset of effect, increased half-life and improved ocular surface retention.

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Manufacturability of drug candidates. We use the AMP-Rx platform to generate drug candidates that have favorable
manufacturing characteristics, such as high production yield, improved solubility and thermal stability. We believe these characteristics will allow us to minimize costly or difficult production and purification processes.

Our Strategy

Our goal is to become a leading biopharmaceutical company
focused on developing and commercializing novel protein therapeutics to treat diseases of the eye. The key elements of our strategy in support of this goal are to:

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Complete clinical development of and seek marketing approval for EBI-005 for the treatment of dry eye disease. Currently,
we are devoting most of our efforts to completing the clinical development of EBI-005. We are initiating a pivotal Phase 3 clinical program consisting of two Phase 3 clinical trials evaluating the safety and efficacy of EBI-005 for the treatment of
moderate to severe dry eye disease and a separate clinical trial evaluating the safety of treatment with EBI-005 for one year. We have begun screening patients for our first Phase 3 trial and expect to begin randomizing and treating patients in this
trial by early February 2014. Based on our estimates regarding patient enrollment, we expect to have top-line data from our first Phase 3 trial available in early 2015. We also expect to initiate our separate safety trial in 2014. We currently
intend to initiate our second Phase 3 trial after reviewing top-line data from our first Phase 3 trial, although we may later decide to initiate our second Phase 3 trial while our first Phase 3 trial is ongoing. If the results of both of our Phase 3
trials and our separate safety trial are favorable, we plan to submit a BLA to the FDA, seeking approval of EBI-005 for the treatment of dry eye disease in the United States in the second half of 2016.

Expand use of EBI-005 for additional ocular indications. We are evaluating other ocular surface diseases in which we
believe elevated levels of IL-1 signaling play a role in the underlying biology of the disease and for which we believe EBI-005 treatment may be beneficial. In early 2014, we plan to initiate a Phase 2 clinical trial to assess the potential
therapeutic benefit of EBI-005 for the treatment of allergic conjunctivitis in patients who have not responded adequately to antihistamines and mast cell stabilizers. We expect that top-line data from this Phase 2 trial could be available before the
end of 2014.

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Maximize commercial potential of EBI-005. We hold worldwide commercialization rights to EBI-005. We believe that the
specialists in the United States who treat most of the moderate to severe dry eye disease patients are sufficiently concentrated that if EBI-005 receives marketing approval in the United States, we could effectively promote EBI-005 to these
specialists with a specialty sales and marketing group. Therefore, we may decide to build our own focused, specialty sales force in order to commercialize EBI-005 in the United States. We intend to enter into strategic collaborations for the
development and commercialization of EBI-005 outside of the United States.

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Apply AMP-Rx platform to build a pipeline of product candidates for the treatment of eye diseases. We use our AMP-Rx
platform to rationally design, engineer and generate a pipeline of innovative protein therapeutic candidates that target cytokines that we believe are central to diseases of the eye. We have designed, engineered and generated EBI-005 and our other
product candidates using our AMP-Rx platform. Our two most advanced preclinical product candidates are EBI-029 for the treatment of DME and EBI-028 for the treatment of uveitis. Both of these product candidates are in early preclinical research and
may require further optimization. We plan to continue to apply our platform to expand our product pipeline.

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Pursue collaborative and other strategic opportunities. We have established a collaboration with ThromboGenics N.V., or
ThromboGenics, a European based, publicly held biopharmaceutical company focused on developing and commercializing innovative ophthalmic medicines. In this collaboration, we apply our proprietary AMP-Rx platform to design, engineer and generate
protein therapeutics that can modulate a specific novel pathway in retinal disease and that have key pharmaceutical attributes. This collaboration provides us with funding for the specific program that is the subject of the collaboration and allows
us to apply our AMP-Rx platform to a product discovery effort we might not otherwise have pursued. We plan to evaluate opportunities to enter into other collaborations that may contribute to our ability to advance our product candidates and to
progress concurrently a range of discovery and development programs. We also plan to evaluate opportunities to in-license or acquire the rights to other products, product candidates or technologies for the treatment of eye diseases.

Our Product Development Programs

We apply our proprietary AMP-Rx platform to
the discovery and development of protein therapeutics to treat diseases of the eye. Our therapeutic approach is based on the role of cytokines in diseases of the eye, our understanding of the structural biology of cytokines and our ability to
rationally design and engineer proteins to modulate the effects of cytokines. We have generated a product pipeline of innovative protein therapeutic candidates that address ocular diseases that are not well served by current therapies.

The following table summarizes key information about our product development programs.

Our Product Candidates

Ocular Surface Diseases

Ocular surface diseases are disorders of the
surface of the cornea, the transparent layer that forms the front of the eye, and the conjunctiva, the membrane covering the inside of the eyelids and white part of the eye. These diseases include dry eye disease and allergic conjunctivitis.
Patients with ocular surface diseases may suffer from difficulty with routine visual activities, loss of vision, discomfort, infections, erosion of the cornea, ulcerations and scarring of the cornea. We believe that the optimal approach to treatment
of diseases of the ocular surface is a potent active ingredient formulated with a comfortable solution, or vehicle, for topical delivery.

Dry Eye Disease

Dry eye disease is a potentially debilitating disease of the eye that may, in its most severe forms, have sight-threatening corneal
complications. Dry eye disease often is classified as mild, moderate or severe based on clinical symptom severity. Dry eye disease is one of the leading causes of patient visits to eye care professionals in the United States. According to Market
Scope, approximately 68 million people in the United States, European Union, Japan and other developed markets have dry eye disease, including approximately 26 million people who suffer from the moderate to severe form of dry eye disease. According
to Market Scope, approximately 19 million people in the United States have dry eye disease, including approximately seven million people who suffer from the moderate to severe form of dry eye disease.

Current Treatments. The
current standard of care for moderate to severe dry eye disease includes artificial tears and topical anti-inflammatory and immune-modulating drugs. Artificial tears act as a wetting agent. They are available as over-the-counter treatments and are
usually considered the first line of therapy for patients with mild disease. Artificial tears are effective supplements to other therapies in the treatment of moderate to severe dry eye disease, but they generally are not sufficient as a
monotherapy. The anti-inflammatory and immune-modulating drug market for the treatment of moderate to severe dry eye disease consists primarily of Restasis, which is approved for use in the United States, and off-label use of corticosteroids. There
are no drugs approved in the European Union for the treatment of dry eye disease.

Corticosteroids applied topically, or directly to the surface of the eye, have been shown to
be effective in the treatment of moderate to severe dry eye disease. However, topically applied corticosteroids have been associated with a higher risk of developing glaucoma and cataracts and an increased risk of ocular infection. These are serious
side effects that significantly limit the use of corticosteroids.

Restasis is a topically applied, ophthalmic formulation of the immune-modulating drug cyclosporine. Restasis is not approved for the treatment of the symptoms of dry eye disease, but only for increasing
tear production in patients whose tear production is presumed to be suppressed due to ocular inflammation associated with dry eye disease. Annual worldwide sales of Restasis have increased from approximately $444 million in 2008 to approximately
$792 million in 2012. In clinical trials, Restasis increased tear production, a sign of dry eye disease, after six months of treatment in approximately 15% of treated patients as compared to approximately 5% of patients in the control groups. These
increases in tear production generally were observed after between three and six months of treatment. In these same clinical trials, approximately 17% of patients reported ocular burning following the use of Restasis. We believe that there remains a
significant unmet medical need for new treatments for patients suffering from moderate to severe dry eye disease.

Biology. At the onset of dry eye disease, the tear film that is necessary for maintaining the health
of the surface of the eye and for providing clear vision breaks down. The precise causes of the breakdown are not well understood but may include hormonal changes, infection or inflammation of the eye, the use of drugs with drying effects such as
anti-depressants, contact lens use, smoke and very dry air. Without adequate wetting, the surface of the eye becomes stressed. The symptoms of dry eye disease include discomfort, pain, burning, itching and visual disturbance.

We believe that stress on the ocular surface as a result
of the loss of an adequate tear film leads to the signs and symptoms of dry eye disease. As a result of this stress on the ocular surface, various cells and tissues of the eye produce inflammatory mediators, such as the cytokines interleukin-1alpha,
or IL-1a, and interleukin-1beta, or IL-1b. These cytokines, which we refer to together as IL-1, bind to the IL-1 receptor found on many different cell types in
the cornea and conjunctiva. This binding and the resulting receptor signaling initiate and maintain an inflammatory response in the tissues of the eye. The resulting inflammation then leads to the further local production of inflammatory cytokines.
This cascade of inflammation results in a state of chronic inflammation and ocular surface damage. This damage is indicative of dry eye disease and can be measured by the staining of the ocular surface with the dye fluorescein, a measure known as
CFS.

IL-1a and IL-1b also can bind to the IL-1
receptor on nerve cells. This binding and the resulting receptor signaling stimulates nerve cells, triggers nociception, or feelings of pain, and can result over time in chronic hyperalgesia, or increased sensitivity to pain. Nociception and
hyperalgesia lead to patient reported symptoms of discomfort, ocular pain, which patients may report as soreness, stinging or burning, and difficulty with routine visual activities, such as using a computer, driving a car or watching television.
These subjective symptoms of dry eye disease can be evaluated through a variety of patient-reported and physician-reported assessments. These usually take the form of questionnaires which provide data that can be scored to provide a quantitative
measure of symptom severity.

As depicted in the graphic below, stress on the ocular surface leads to the excess
production of IL-1. IL-1 initiates and maintains both inflammatory and neural responses in the tissues of the eye. The inflammatory response results in ocular surface damage, a sign of dry eye disease. The inflammatory response also results in
continued production of IL-1 and chronic inflammation, which manifests as various symptoms of dry eye disease. The neural response results in feelings of and hypersensitivity to pain, which are persistent symptoms of dry eye disease.

The biological activities
of IL-1 suggest that blocking IL-1 receptor signaling should have a dual function and reduce both a sign of dry eye disease, specifically ocular surface inflammation and injury, and a symptom of dry eye disease, specifically ocular pain and
discomfort. In the case of dry eye disease, IL-1a and IL-1b, acting independently or in concert, both drive IL-1 receptor signaling. As a result, a therapy
that blocks only IL-1a or IL-1b may not have the desired effect of completely blocking IL-1 receptor signaling and alleviating the signs and symptoms of dry
eye disease. We believe that a better approach is to block the IL-1 receptor itself so neither IL-1a nor IL-1b can bind to the receptor and trigger receptor
signaling.

EBI-005  a Novel IL-1 Receptor Antagonist

Our most advanced product candidate is
EBI-005, a recombinant protein which binds with the IL-1 receptor and blocks, or antagonizes, IL-1 receptor signaling. We have designed, engineered and generated EBI-005 using our AMP-Rx platform and are developing EBI-005 as a topical, eye-drop
treatment for dry eye disease and allergic conjunctivitis. EBI-005 prevents the binding of both IL-1a and IL-1b to the IL-1 receptor. When the IL-1 receptor is blocked by EBI-005, the IL-1 receptor is unable to transmit the biological signals that we believe are responsible for pain, discomfort, itching and inflammation in ocular surface diseases.

Design and Attributes of EBI-005

We designed EBI-005 based on our
understanding of the molecular structure of the IL-1 receptor and two of the molecules, or ligands, that are known to bind effectively to this receptor, IL-1b and IL-1 receptor antagonist, or IL-1Ra. We
engineered EBI-005 to combine the portions of IL-1b and IL-1Ra having desirable biophysical properties and IL-1 receptor binding characteristics. We engineered EBI-005 as a pure antagonist to the IL-1
receptor, which means that EBI-005 binds to the IL-1 receptor without triggering receptor signaling. We also designed EBI-005 to have the following product attributes that we believe improve its potential utility as a topical therapeutic:

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Rapid onset of action. We have designed EBI-005 to be a potent blocker of IL-1. In a biochemical study of receptor
binding, EBI-005 bound more rapidly and up to 500 times more strongly to the IL-1 receptor than the natural ligands IL-1b and IL-1Ra. In a mouse model of dry eye disease, treatment with EBI-005 resulted
in a greater reduction in CFS from baseline at seven days and at 11 days when compared to the reduction in CFS from baseline with IL-1Ra treatment. We believe the potency of EBI-005 may result in a rapid onset of symptomatic relief.

Comfortable for patients. We have optimized EBI-005 for topical, ophthalmic delivery and have formulated it with a
preservative-free comfortable solution, or vehicle, for delivery as an eye drop. We believe patient comfort is an important factor in patient compliance and physician recommendation of a topical drug for diseases of the ocular surface.

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Convenient dosing. We have designed EBI-005 to bind tightly to the IL-1 receptor and block it for an extended period of
time. We have measured the duration of this receptor binding in biochemical tests outside the body, or in vitro. Based on these tests and our understanding of the natural cycling of the IL-1 receptor from the cell surface to the cell
interior, we believe EBI-005 remains bound to an IL-1 receptor during the entire period the receptor is present on the surface of a cell. We believe a long duration of receptor binding may allow for a convenient dosing schedule.

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Stable dosage form. We designed EBI-005 to be a thermally stable protein product. In analytical tests, EBI-005 was stable
for at least five months at room temperature. We believe room temperature stability without the need for refrigeration is an important convenience for patients.

The design of EBI-005 as a combination of those portions of
IL-1b and IL-1Ra having desirable biophysical properties and IL-1 receptor binding characteristics is depicted in the graphic below.

EBI-005 Binds
Tightly to and Blocks the IL-1 Receptor

We believe IL-1 plays a central role in dry eye disease and that EBI-005 has the potential to treat both the signs and symptoms of dry eye
disease by binding tightly to and blocking the transmission of biological signals by the IL-1 receptor. EBI-005 blocks the inflammatory and neuropathic activities of IL-1 by binding to the IL-1 receptor during both the initiation and maintenance of
the cycle of pain and inflammation in dry eye disease.

In 2013, the peer-reviewed journal JAMA Ophthalmology
published the results of an exploratory Phase 1/2 clinical trial in 75 patients conducted by one of our scientific co-founders, Dr. Reza Dana, at the Massachusetts Eye and Ear Infirmary using another IL-1 blocker, anakinra, to treat moderate to
severe dry eye disease. Anakinra is approved for subcutaneous administration for the treatment of rheumatoid arthritis and is marketed under the brand name Kineret. For this proof-of-concept study, the investigators compounded, or reformulated,
anakinra in eye drops at two different concentrations for topical administration. In this double masked, placebo controlled study, patients with dry eye disease received either anakinra or a placebo control consisting of the vehicle, which was a
commercially available eye drop the investigators used to formulate anakinra for topical, ophthalmic application. The investigators in this trial required patients who were using anti-inflammatory therapies, including Restasis, to discontinue their
use for 30 days prior to enrollment and throughout this trial. Patients were allowed to continue their use of artificial tears and therapies other than anti-inflammatory therapies. Thirty patients received anakinra at the lower dose of 25 mg/ml and
15 patients received anakinra at the higher dose of 50 mg/ml. Thirty patients received vehicle control. Patients were treated for 12 weeks with a follow up at 16 weeks.

In this trial, there was an improvement in CFS, a sign of dry
eye disease, in patients treated with anakinra from baseline at six weeks and at 12 weeks. We believe that the magnitude of the CFS response was clinically relevant for the lower dose anakinra treatment group at six weeks and at 12 weeks. We believe
that the magnitude of the CFS response was clinically relevant for the higher dose anakinra treatment group only at six weeks. However, none of these differences was statistically significant when compared to the difference from baseline observed in
patients who received vehicle control. We determine statistical significance based on a widely used, conventional statistical method that establishes the p-value of clinical results. Typically, a p-value of 0.05 or less represents statistical
significance. There also was an improvement in patient symptoms as measured by the OSDI score in patients treated with anakinra from baseline at six weeks and at 12 weeks. We believe that the magnitude of improvement in patient symptoms as measured
by the OSDI score was clinically relevant for both the lower dose and higher dose anakinra treatment groups at six weeks and at 12 weeks, and the differences from baseline at six weeks and at 12 weeks were statistically significant for both the
lower dose and higher dose anakinra treatment groups when compared to the differences from baseline observed in patients who received vehicle control.

We subsequently conducted an additional, retrospective analysis of the results of this trial. In this analysis, we observed in patients
treated with anakinra that the improvement from baseline at six weeks and at 12 weeks in pain and discomfort, as measured by the painful or sore eyes question on the OSDI, was the largest contributor to the improvement in patient symptoms as
measured by the OSDI score. We then analyzed the data on pain and discomfort and observed a statistically significant improvement from baseline in pain and discomfort, as measured by the painful or sore eyes question on the OSDI, in the lower dose
anakinra treatment group at six weeks (p=0.01) and at 12 weeks (p=0.04) and higher dose anakinra treatment group at six weeks (p=0.01) and at 12 weeks (p=0.04) compared to the improvement from baseline in the vehicle control group. We believe that
the clinical experiences with anakinra are relevant to our development of EBI-005 because the therapeutic targets and mechanisms of action of anakinra and EBI-005 are similar. However, based on our studies of the biophysical characteristics of
anakinra, we do not believe that it can be formulated for topical ophthalmic delivery in a convenient format on a commercial basis because at the concentration shown to be effective in the anakinra trial, anakinra is not stable under the conditions
encountered during vialing in a standard blow-fill-seal vial configuration. We believe that the blow-fill-seal vial configuration is the most cost-effective process for delivering a preservative-free eye drop. We believe that a drug for dry eye
disease should be preservative-free because chronic exposure to preservatives may irritate the ocular surface. In addition, based on our own biochemical studies, we do not believe that the particular formulation of anakinra used in the anakinra
trial can be used for topical ophthalmic delivery in a convenient format on a commercial basis because at the concentration shown to be effective in the anakinra trial:

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anakinra is not stable in solution when agitated, which means that routine handling of a topical, ophthalmic formulation of anakinra by a patient could
result in a change in the concentration of anakinra received by the patient upon dosing; and

anakinra is not stable at room temperature. We believe room temperature stability without the need for refrigeration is an important convenience for
patients.

Clinical Development of EBI-005

We have completed two clinical trials
with EBI-005. In 2012, after submitting an investigational new drug application, or IND, to the FDA for the purpose of conducting clinical trials for the treatment of dry eye disease, we completed a Phase 1 clinical trial evaluating the safety and
tolerability of EBI-005 in healthy volunteers. In 2013, we completed a Phase 1b/2a clinical trial evaluating the safety, tolerability and biological activity of EBI-005 in patients with moderate to severe dry eye disease. We are initiating a pivotal
Phase 3 clinical program consisting of two Phase 3 clinical trials evaluating the safety and efficacy of EBI-005 for the treatment of moderate to severe dry eye disease and a separate clinical trial evaluating the safety of treatment with EBI-005
for one year. We have begun screening patients for our first Phase 3 trial and expect to begin randomizing and treating patients in this trial by early February 2014. Based on our estimates regarding patient enrollment, we expect to have top-line
data from our first Phase 3 trial available in early 2015. We expect to initiate our separate safety trial in 2014.

We currently intend to initiate our second Phase 3 trial after reviewing top-line data from our first Phase 3 trial, although we may later
decide to initiate our second Phase 3 trial while our first Phase 3 trial is ongoing. We will base our decision on when to initiate our second Phase 3 trial upon our assessment of the benefits of potentially accelerating the completion of our
pivotal Phase 3 clinical program and the risk that we will not have potentially valuable information from the completion of the first Phase 3 trial that would suggest that changes to the second Phase 3 trial would have improved its design or
likelihood of success. If the results of both of our Phase 3 trials and our separate safety trial are favorable, we plan to submit a BLA with the FDA seeking approval of EBI-005 for the treatment of dry eye disease in the United States in the second
half of 2016.

We designed our Phase 1b/2a
trial to evaluate the safety and tolerability of EBI-005 and to provide us with insights regarding dose, patient selection and efficacy endpoints for the design of our planned Phase 3 trials. When we evaluated the results of the anakinra trial,
we concluded that we would need to conduct a clinical trial in approximately 650 patients in order to determine with statistical significance a difference in improvements in one sign and one symptom of dry eye disease between patients treated
with EBI-005 at concentrations of 5 mg/ml and 20 mg/ml and a vehicle control.

We believed that a trial with approximately 650 patients as our first clinical trial of EBI-005 in patients with dry eye disease was impractical. Accordingly, we designed our Phase 1b/2a trial as a
smaller trial to determine if treatment with EBI-005 would result in the magnitude of change from baseline on CFS scores, OSDI scores and OSDI scores specifically on the painful or sore eyes question that had been observed by Dr. Dana with
anakinra treatment. CFS is a quantitative measure of the severity of dry eye disease and is a widely used and validated sign of dry eye disease. CFS is measured on a scale from zero, which means no staining and no sign of damage, to a maximum of
between three and 15, depending on the particular scale used, which means extensive staining and damage. The OSDI is a commonly used 12-item questionnaire that is designed to determine how a patient experiences the feeling of dry eye disease, the
impact that dry eye disease has on routine visual function and what environmental triggers exacerbate symptoms. The OSDI score is a composite of the scores on the individual questions and ranges from zero, which means the patient is experiencing no
symptoms, to 100, which means the patient is experiencing severe symptoms. Individual questions in the OSDI, which have scores that range from zero to four, also can be evaluated as measures of specific symptoms.

We formulate the active pharmaceutical ingredient of EBI-005
with a preservative-free solution, or vehicle, for topical, ophthalmic delivery as an eye drop. In descriptions of our clinical trials in this prospectus, we refer to this formulation also as EBI-005. The vehicle is a proprietary mixture of
excipients that are commonly used in eye drops. In each of our clinical trials the placebo control group receives vehicle, which is the same as the EBI-005 formulation used in the trial except that it contains none of the EBI-005 active
pharmaceutical ingredient.

We tested EBI-005 at concentrations of 5 mg/ml and 20 mg/ml in our Phase 1b/2a trial. We
analyzed efficacy data by first combining both EBI-005 dose groups, as specified in the statistical analysis plan, into a single combined EBI-005 treatment group and then by individual EBI-005 dose groups. We designed our Phase 1b/2a trial to
evaluate differences in patient responses to EBI-005 on multiple efficacy endpoints without an expectation of achieving statistical significance compared to vehicle control. We believed that the results of our Phase 1b/2a trial would provide a
foundation for making informed choices regarding dose of EBI-005, patient eligibility criteria and measures of clinical efficacy for our planned Phase 3 trials. As described below, we have incorporated our evaluations of the results of our Phase
1b/2a trial into the design of our planned pivotal Phase 3 clinical program. The pivotal Phase 3 clinical program described in this prospectus is based on our current protocols and is subject to change.

Planned Pivotal Phase 3 Clinical Program of EBI-005 for the Treatment of
Dry Eye Disease

Our planned pivotal
Phase 3 clinical program will consist of two Phase 3 clinical trials to evaluate the safety and efficacy of EBI-005 from baseline at 12 weeks at a concentration of 5 mg/ml for the treatment of moderate to severe dry eye disease and a separate
clinical trial evaluating the safety of treatment with EBI-005 at the same concentration for one year. We plan to conduct each of our Phase 3 trials in approximately 650 patients. We have begun screening patients for our first Phase 3 trial and
expect to begin randomizing and treating patients in this trial by early February 2014. We plan to conduct our first Phase 3 trial at up to 40 centers in the United States. If the results of our first Phase 3 trial are favorable, we currently intend
to initiate our second Phase 3 trial after reviewing top-line data from our first Phase 3 trial. However, we may later decide to initiate our second Phase 3 trial while our first Phase 3 trial is ongoing. We plan to conduct our second Phase 3 trial
at up to 40 centers in the United States and Europe. We will conduct each of our Phase 3 trials in an outpatient setting in a natural environment. We will not use a controlled adverse environment chamber.

We have designed our pivotal Phase 3 clinical program based
on the results we observed in our Phase 1b/2a clinical trial of EBI-005 for the treatment of dry eye disease. We met with the FDAs Division of Transplant and Ophthalmology Products in July 2013 to discuss our planned pivotal Phase 3 clinical
program. Based in part on the discussions at that meeting, we believe that if the results of both of our Phase 3 trials are favorable, they will be sufficient, together with our separate safety trial, to support a BLA submission to the FDA seeking
approval of EBI-005 for the treatment of dry eye disease in the United States. We are currently seeking scientific advice from the European Medicines Agency, or EMA, to confirm the requirements for pivotal trials in the European Union.

Planned Phase 3 Clinical Trial Endpoints

Based on our communications with the
FDA, we believe that in order to support a BLA submission to the FDA seeking approval of EBI-005 in the United States, we must demonstrate in two Phase 3 clinical trials a statistically significant improvement in at least one sign and one
symptom of dry eye disease in patients treated with EBI-005 compared to improvement on the same sign and symptom in patients receiving vehicle. We plan to specify a sign and a symptom as co-primary endpoints in our Phase 3 trials. We expect that one
co-primary endpoint will be defined as a change in CFS score, a sign of dry eye disease, from baseline at week 12 with EBI-005 treatment compared to change from baseline at week 12 with vehicle control. We expect the other co-primary endpoint will
be defined as improvement in pain and discomfort as measured by the painful or sore eyes question on the OSDI, a symptom of dry eye disease, from baseline at week 12 with EBI-005 treatment compared to change from baseline at week 12 with vehicle
control.

We expect to include change in the OSDI
score from baseline at week 12 with EBI-005 treatment compared to change from baseline at week 12 with vehicle control as another measure of change in symptoms and as a secondary endpoint in our first Phase 3 trial. We expect also to include as
secondary endpoints in our first Phase 3 trial changes in CFS in specified regions of the cornea from baseline at week 12 with EBI-005 treatment compared to changes from baseline at week 12 with vehicle
control. Other secondary endpoints in our first Phase 3 trial will include the evaluation of the change in all primary and secondary endpoints from baseline at week

nine. In addition to efficacy endpoints, other secondary endpoints in these Phase 3 trials will include the evaluation of the safety, tolerability and immunogenicity, or the tendency to elicit an
antibody response, of EBI-005 after 12 weeks of dosing.

If we demonstrate a statistically significant improvement from baseline in the EBI-005 treatment group relative to the improvement from baseline in the vehicle control group on a pre-specified secondary
endpoint in the first of our Phase 3 trials, we may decide to substitute that secondary endpoint as a co-primary endpoint in our second Phase 3 trial prior to initiation of this second Phase 3 trial. If we demonstrate a statistically significant
improvement from baseline in the EBI-005 treatment group relative to the improvement from baseline in the vehicle control group on the substituted co-primary endpoint in the second Phase 3 trial, we may combine the results of the evaluation of the
pre-specified secondary endpoint in the first Phase 3 trial with the results of the substituted pre-specified co-primary endpoint in the second Phase 3 trial, in support of our application for marketing approval of EBI-005. Based on our meeting with
the FDA in July 2013, we believe that, although it would be a review issue at the time of our application for marketing approval, the FDA may consider this an acceptable means of meeting the requirement that we duplicate in two Phase 3 trials a
statistically significant improvement on a clinically relevant sign or symptom.

Planned Phase 3 Clinical Trial Design

Each of our planned Phase 3 trials will be a double masked, randomized, placebo controlled study. Patients will be screened on the basis of eligibility criteria at a first visit. We expect that patients
who qualify for enrollment will receive topical administration in each eye three times per day for one week of vehicle. At the conclusion of this one-week run-in period, we will reassess patients against additional eligibility criteria. Those
patients who qualify under these additional criteria will be randomly assigned, or randomized, to either an EBI-005 treatment group or a vehicle control group. We refer to the time at which we randomize a patient as baseline.

Eligible patients will be at least 18 years of age, with
moderate to severe dry eye disease. We expect that additional eligibility criteria will include the following:

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OSDI score greater than or equal to 23 and less than or equal to 75 at screening. A score greater than or equal to 23 and less than or equal to 32 is
considered moderate dry eye disease. A score greater than or equal to 33 is considered severe dry eye disease.

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OSDI score greater than or equal to 19 and less than 50 at randomization.

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CFS score of greater than or equal to six and less than 15 on the National Eye Institute, or NEI, scale at screening. A score greater than or equal to
six and less than 15 is consistent with moderate to severe dry eye disease.

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CFS score of greater than or equal to five and less than 15 on the NEI scale at randomization.

During our Phase 1b/2a trial of EBI-005, we observed greater
variability in clinical response in patients who had an OSDI score greater than or equal to 50 at randomization. We believe this increased variability in clinical response made it more difficult to detect differences between the combined EBI-005
treatment groups and the vehicle control group on the primary and secondary efficacy endpoints. In our Phase 3 trials, we will exclude patients with an OSDI score greater than or equal to 50 at randomization because we believe this criteria will
reduce variability in clinical response and improve our ability to detect differences between the EBI-005 treatment group and the vehicle control group on the co-primary and secondary efficacy endpoints.

We expect that patients who are randomized will receive
topical administration in each eye three times per day for 12 weeks of EBI-005 at 5 mg/ml or vehicle control beginning at randomization. The patients will undergo study evaluations at weeks one, three, six, nine and 12 following randomization. The
last dose of EBI-005 will be completed 12 weeks after randomization. We will require patients to attend a final visit three weeks after their week 12 visit.

The timeline for our first Phase 3 trial of EBI-005 and number of patients, or subjects, to
be randomized into the EBI-005 treatment and vehicle control groups are depicted in the graphic below.

The following aspects of
the design of our Phase 3 trials are based on the results we observed in our Phase 1b/2a trial of EBI-005 for the treatment of dry eye disease:

Eligibility CriteriaOSDI Score. Our Phase 3 trials of EBI-005 will include patients with OSDI
scores at screening greater than or equal to 23 and less than or equal to 75 and with OSDI scores at randomization greater than or equal to 19 and less than 50. In a retrospective analysis of the results of our Phase 1b/2a trial, in which we
included patients with OSDI scores at screening greater than or equal to 23 and less than 90 and with OSDI scores at randomization greater than or equal to 19, we observed in patients with OSDI scores less than 50 at randomization less variability
in clinical response than we observed in patients with OSDI scores greater than or equal to 50 at randomization. Therefore, we have designed our Phase 3 trials to exclude at randomization patients with an OSDI score greater than or equal to 50. We
believe this will make it more likely that our Phase 3 trials will confirm the trend of greater improvement in clinical response from baseline in the combined EBI-005 treatment groups relative to the improvement from baseline in vehicle control
group that we observed in our Phase 1b/2a trial. We also have designed our Phase 3 trials to exclude at screening patients with an OSDI score greater than 75, as compared to greater than or equal to 90 in our Phase 1b/2a trial. We believe we can
increase the likelihood of recruiting patients who will have an OSDI score less than 50 at randomization by excluding patients with OSDI scores greater than 75 at screening.

Eligibility CriteriaCFS
Score. We expect to include patients with CFS scores greater than or equal to six and less than 15 on the NEI scale at screening or greater than or equal to five and less than 15 on the NEI scale at randomization.
These are the same criteria we used in our Phase 1b/2a trial, except that we did not exclude patients with a CFS score of 15 at randomization in our Phase 1b/2a trial. The determination of CFS score is made by microscopic examination of the cornea
by the physician who has to assess the extent of staining in each of five regions of the ocular surface. We have developed an eye-piece for the microscope that projects a grid pattern onto the cornea that divides it into the five regions to be
assessed. We believe this helps the physician and reduces some of the subjectivity inherent in the assessment. By reducing the subjectivity, we believe we generate a more reliable data set for statistical analysis.

Use of Rescue Artificial
Tears. We plan to prohibit the use of rescue artificial tears by patients in our Phase 3 trials. In our Phase1b/2a trial, we measured artificial tear usage by patients as a pre-specified exploratory

endpoint. Mean and median artificial tear usage were significantly higher in patients in the vehicle control group than those in the EBI-005 treatment groups. We believe that the use of
artificial tears by patients in the vehicle control group could have had an impact on the sign and symptom assessments in our Phase 1b/2a trial. If such assessments improved because of the use of artificial tears, we believe these improvements would
have occurred disproportionately in the vehicle control group because we observed that patients in the vehicle control group used more artificial tears and a higher percentage of patients in the vehicle control group used large amounts of artificial
tears compared to the combined EBI-005 treatment groups. As a result, we believe that the differences in our Phase 1b/2a trial in the sign and symptom assessment scores between the vehicle control group and the combined EBI-005 treatment groups
might have been larger if artificial tears were not used.

Dose of EBI005. Overall in our Phase 1b/2a trial, we did not observe any significant differences between administration of EBI-005 three times per day at a
concentration of 5 mg/ml and at a concentration of 20 mg/ml. Based on our understanding of the mechanism of action and potency of EBI-005, we did not expect to observe any such differences. In our Phase 3 trials, we will be evaluating topical
administration of EBI-005 three times per day at a concentration of 5 mg/ml.

Efficacy EndpointCFS Score. In a retrospective analysis of the results of our Phase 1b/2a trial, we observed a trend of greater improvement of CFS scores from
baseline at week six in the combined EBI-005 treatment groups relative to the improvement from baseline in the vehicle control group when we excluded the seven patients who had major protocol deviations and included only patients who had baseline
OSDI scores less than 50. We believe this trend is consistent with the results of the anakinra trial. In our first Phase 3 trial, we will pre-specify the change in CFS scores from baseline at week 12 as a co-primary efficacy endpoint.

Efficacy EndpointOSDI
Pain. In a retrospective analysis of the results of our Phase 1b/2a trial, we observed a trend of greater improvement of the scores on the OSDI question regarding painful or sore eyes from baseline at week six in the
combined EBI-005 treatment groups relative to the improvement from baseline in the vehicle control group when we excluded the seven patients who had major protocol deviations and included only patients who had baseline OSDI scores less than 50. We
believe this trend is consistent with our understanding of the mechanism of action of EBI-005 and the trends we observed in our retrospective analysis of the results of the anakinra trial. In our first Phase 3 trial, we will pre-specify the change
in scores from baseline on the OSDI question regarding painful or sore eyes from baseline at week 12 as a co-primary efficacy endpoint.

Number of Patients. Based on the results of our Phase 1b/2a trial, we believe that each of our Phase
3 trials will be adequately powered with approximately 650 patients to detect a difference between the EBI-005 treatment group and vehicle control on our proposed co-primary efficacy endpoints. We plan to perform a sample size reassessment on a
masked basis of all randomized patients after the first one-third of the randomized patients complete 12 weeks of treatment with EBI-005 in our first Phase 3 trial to determine whether we need to increase the number of patients we randomize in this
trial. We plan to conduct this sample size reassessment to determine whether the observed variability of the clinical response is greater than the variability we expected based on the results of our Phase 1b/2a trial. If we need to increase the
number of patients, we plan to randomize an equal number of additional patients in each treatment arm of our first Phase 3 trial. We expect to engage a contract research organization, or CRO, to conduct this sample size reassessment, and we expect
not to receive any information other than whether we need to randomize additional patients. We do not believe this masked sample size reassessment will compromise our final statistical analysis. We do not expect that any increase in the number of
randomized patients will have a significant impact on the costs or duration of our first Phase 3 trial.

Duration of Trial. In the anakinra trial, the investigators observed greater improvements on mean
change from baseline on both CFS score and OSDI score at 12 weeks in patients treated with lower dose anakinra compared to vehicle control than was observed at six weeks. We believe that the longer treatment period in our Phase 3 trials may improve
our ability to detect differences between the EBI-005 treatment group and the vehicle control group on our co-primary efficacy endpoints.

Vehicle. We have modified the vehicle in our
formulation of EBI-005 for our Phase 3 trials relative to the vehicle in our formulation of EBI-005 for our Phase 1b/2a trial primarily by removing carboxymethyl cellulose, or CMC, a common ingredient in artificial tears. CMC is not included in
Restasis. We made this refinement to make our formulation of EBI-005 suitable for vialing in an industry standard single-use format, to increase stability of EBI-005 and to improve ease of manufacturing. We believe our new formulation remains
comfortable to patients and that the removal of CMC will not meaningfully affect patient responses.

Natural Environment. We intend to conduct our Phase 3 trials in a natural environment and not to use a controlled adverse environment chamber. We also conducted our
Phase 1b/2a trial in a natural environment. A controlled adverse environment chamber historically has been used in trials of product candidates for the treatment of dry eye disease. A controlled adverse environment chamber allows the clinical
investigator to exacerbate the signs and symptoms of dry eye in a controlled manner by regulating humidity, temperature, airflow, lighting conditions and visual tasking. However, we believe that the controlled adverse environment chamber introduces
differences in the presentation and manifestation of dry eye disease and in patients perceptions of their disease. We believe that the controlled adverse environment chamber does not reflect the environment in which patients experience their
dry eye disease on a daily basis and in which patients and physicians ultimately will judge the benefits of any dry eye disease drug. As a result, we believe that a natural environment is a better setting for the evaluation of EBI-005.

In addition to the two Phase 3 trials required to support
marketing approval of EBI-005 for the treatment of dry eye disease in the United States, we will be required to demonstrate the long-term safety of EBI-005 treatment in a safety trial. To meet this requirement, we plan to conduct a safety trial with
no fewer than 100 patients who will be treated with EBI-005 for one year. We expect that patients in this safety trial will be treated three times a day with EBI-005 at a concentration of 5 mg/ml. During this study, the safety and tolerability of
longer term exposure to EBI-005 will be evaluated, along with immunogenicity and potentially other endpoints that may support the application for marketing approval of EBI-005.

We have begun screening patients for our first Phase 3
trial in our pivotal Phase 3 clinical program and expect to begin randomizing and treating patients in this trial by early February 2014. Based on our estimates regarding patient enrollment, we expect to have top-line data from our first Phase 3
trial available in early 2015. If the results of our first Phase 3 trial are favorable, we plan to conduct a second Phase 3 trial that will be designed to evaluate co-primary endpoints that met the criteria of acceptability in our first Phase 3
trial as co-primary endpoints or as one co-primary endpoint and one secondary endpoint. We expect that our second Phase 3 trial will be designed similarly to the first trial. We currently intend to initiate our second Phase 3 trial after reviewing
top-line data from our first Phase 3 trial, although we may later decide to initiate our second Phase 3 trial while our first Phase 3 trial is ongoing, in which case we would not be able to change the co-primary endpoints in our second Phase 3 trial
based on the results of our first Phase 3 trial. If the results of both Phase 3 trials in our pivotal Phase 3 clinical program and our separate safety trial are favorable, we plan to submit a BLA seeking approval in the United States of EBI-005 for
the treatment of dry eye disease in the second half of 2016.

Completed Phase 1b/2a Clinical Trial in Dry Eye Disease

In the second quarter of 2013, we completed a multicenter, double masked, randomized, placebo controlled Phase 1b/2a clinical trial
evaluating the safety and biological activity of EBI-005 in patients with moderate to severe dry eye disease. We conducted this trial in 74 patients at eight centers in the United States. We conducted this trial in a natural environment. We did not
use a controlled adverse environment chamber.

We
screened patients against eligibility criteria at a first visit. Patients who qualified for enrollment received topical administration in each eye three times per day for one week of vehicle. At the conclusion of the one-week run-in period, we
reassessed patients again against eligibility criteria. Those patients who qualified under these additional criteria were randomized to one of three treatment groups. We refer to the CFS score, OSDI score and other measures taken at randomization as
baseline.

Eligible subjects were at least 18 years of age, with moderate to severe dry eye disease.
Additional eligibility criteria included the following:



OSDI score greater than or equal to 23 and less than 90 at the time of screening;



OSDI score greater than or equal to 19 at randomization;



CFS score greater than or equal to six and less than 15 on the NEI scale at the time of screening; and



CFS score greater than or equal to five at randomization.

Patients who were randomized to a treatment group were
treated in both eyes three times per day for six weeks beginning at randomization. Treatments for the three groups in this trial were as follows:



In the first group, 22 patients received topical administration in each eye three times per day of EBI-005 at a concentration of 20 mg/ml.



In the second group, 22 patients received topical administration in each eye three times per day of EBI-005 at a concentration of 5 mg/ml.



In the third group, 30 patients received topical administration in each eye three times per day of vehicle.

We assessed patients at screening, at randomization, at
evaluation visits on weeks two, four and six following randomization, and at a follow up visit one week after the completion of treatment.

The timeline for our Phase 1b/2a trial of EBI-005 and number of patients randomized into the EBI-005 treatment and vehicle control groups
are depicted in the graphic below.

The principal objective of
our Phase 1b/2a trial was to evaluate the safety and tolerability of six weeks of dosing three times a day with EBI-005 as compared to vehicle control in patients with moderate to severe dry eye disease. The protocol also included other objectives
and pre-specified primary and secondary efficacy endpoints to assist us in the evaluation of the biological and clinical response of patients to EBI-005.

The primary safety endpoints included adverse event reporting, complete ophthalmic
examination, testing for corneal health and assessment of clinical laboratory markers. The primary efficacy endpoint of our Phase 1b/2a trial was the absolute change of OSDI score, a symptom of dry eye disease, at week six from baseline. The
secondary efficacy endpoints of this trial were changes at week six from baseline in the following sign and symptom scores:



CFS score, a sign of dry eye disease.



Symptom assessment in dry eye, or modified SANDE, questionnaire score. The modified SANDE questionnaire is a short questionnaire completed by the
patient that quantifies the frequency and severity of symptoms of dry eye disease using a visual analog scale.



Subject-rated and investigator-rated global symptom assessment, or GSA. The GSA is a short questionnaire that assesses degrees of relief or worsening
of specified signs and symptoms of dry eye disease.



Subject-rated individual ocular symptom assessments of the severity of eyelid itching, the sensation of having a foreign body in the eye and ocular
burning or pain.

Statistical Analysis and Significance

In accordance with the protocol and the statistical analysis
plan, the primary analysis population was the intent-to-treat, or ITT, population, which is all patients enrolled in the trial. There were major protocol deviations with respect to seven of the 74 enrolled patients in the intent-to-treat population.
Five of these deviations occurred in the EBI-005 treatment groups, and two occurred in the vehicle control group. These deviations included two patients, one in each of the EBI-005 treatment groups, who were inadvertently enrolled despite having met
an exclusion criteria of no history of corneal surgery and five patients in the vehicle control group who missed at least one entire days dosing. In accordance with the protocol and the statistical analysis plan, we also conducted analyses on
the 67 enrolled patients in the efficacy evaluable, or EE, population, which excludes those patients with major protocol deviations.

We analyzed efficacy data by first combining both the 5 mg/ml and 20 mg/ml EBI-005 dose groups, as specified in the statistical analysis
plan, and by individual dose groups. Overall, we did not see a meaningful difference in response between the two EBI-005 dose groups on any efficacy measure when we analyzed the data for each separate drug treatment group in either the
intent-to-treat or efficacy evaluable population.

In our Phase 1b/2a trial, the median baseline OSDI score was 50 for all patients at randomization, meaning that 50% of the intent-to-treat
population had baseline OSDI scores of less than 50. During our Phase 1b/2a trial of EBI-005, we observed greater variability in clinical response in patients who had an OSDI score greater than or equal to 50. We believe that increased variability
in clinical response made it more difficult to detect differences between the combined EBI-005 treatment groups and the vehicle control group on the primary and secondary efficacy endpoints. Therefore, we performed additional retrospective analyses
that were not pre-specified primary or secondary endpoints in our Phase 1b/2a trial. In these analyses, we assessed whether patients with OSDI scores of less than 50 at baseline responded differently to EBI-005 treatment than patients with OSDI
scores greater than or equal to 50 at baseline. The results of these analyses are described below. Although a retrospective analysis performed after trial results are unmasked can result in the introduction of bias, we believe that the various
retrospective analyses that we performed will assist us in the assessment of the population of patients with the most robust separation between the treatment and vehicle control groups for both signs and symptoms to inform the design of our planned
Phase 3 trials.

We designed this Phase 1b/2a
trial to measure trends of efficacy, and we did not power the trial to measure with statistical significance the differences in any efficacy endpoints. Therefore, the improvements we observed with respect to pre-specified primary, secondary and
exploratory endpoints and retrospective analyses in the intent-to-treat and efficacy evaluable populations that are described below were not statistically significant when compared to vehicle, except as specifically noted.

We observed in the combined EBI-005
treatment groups in the intent-to-treat population an improvement from baseline in both CFS, a sign of dry eye disease, and OSDI, a symptom of dry eye disease, after six weeks of treatment with EBI-005. We believe that the magnitudes of these
responses were clinically relevant.

The table
below sets forth for the combined EBI-005 treatment groups and the vehicle control group, in each case assessing the intent-to-treat population, the mean score at baseline, mean change from baseline at week six, and the percentage change from
baseline at week six on the following primary and secondary efficacy endpoints:



the primary efficacy endpoint of change from baseline in OSDI score; and



the secondary efficacy endpoint of change from baseline in CFS.

Combined EBI-005treatment groups(ITT population)(n = 44)

Vehicle
control group(ITT population)(n =
30)

OSDI

CFS

OSDI

CFS

Mean Score at Baseline

49.8 Points

9.1 Points

52.6 Points

8.8 Points

Mean Change from Baseline at Week Six

18.9 Points

3.0 Points

19.0 Points

2.7 Points

Percentage Change from Baseline at Week Six

38%

33%

36%

31%

We observed improvements in
the combined EBI-005 treatment groups in the intent-to-treat population from baseline through week six on each of the secondary efficacy endpoints of modified SANDE questionnaire score, subject-rated and investigator-rated GSA and subject-rated
individual ocular symptom assessments of the severity of eyelid itching, the sensation of having a foreign body in the eye and ocular burning or pain. However, the differences between the improvements we observed in the combined EBI-005 treatment
groups from baseline at week six and the improvements we observed in the vehicle control group from baseline at week six were not statistically significant for any of these measures. We do not plan to use any of these measures as primary or
secondary endpoints in our planned Phase 3 trials.

Analyses of Efficacy EndpointsEfficacy Evaluable Population

As noted above, there were major protocol deviations with respect to seven of the 74 enrolled patients in the
intent-to-treat population. As a result, we believe the efficacy evaluable population, which excludes those patients with major protocol deviations, is a more appropriate population on which to conduct further analyses. The results of our additional
retrospective analyses are presented below only with respect to the efficacy evaluable population. The results of pre-specified analyses of the corresponding primary and secondary efficacy endpoints with respect to the efficacy evaluable population
also are presented below.

We observed in patients
with OSDI scores less than 50 at randomization less variability in clinical response than we observed in patients with OSDI scores greater than or equal to 50 at randomization. We believe that increased variability in clinical response in the total
efficacy evaluable population made it more difficult to detect differences between the EBI-005 treatment groups and vehicle control. We refer to the efficacy evaluable population with OSDI scores of less than 50 at randomization as the EE50
population.

Retrospective
AnalysisOSDI Score. In the total efficacy evaluable population and in patients in the EE50 population, we observed an improvement of OSDI scores from baseline at week six in the combined EBI-005 treatment groups.
We believe the magnitude of the response was clinically relevant. We also observed that the trend in the improvement in OSDI scores from baseline at week six favoring the combined EBI-005 treatment groups compared to the improvement in OSDI scores
from baseline at week six in vehicle control was greater in the EE50 population than in the total efficacy evaluable population.

The table below sets forth with respect to each of the combined EBI-005 treatment groups and
the vehicle control group in the total efficacy evaluable population and in the EE50 population:



the mean OSDI score at baseline;



the mean change in OSDI score from baseline to week six; and



the percentage change in OSDI score from baseline to week six.

OSDI score

Combined EBI-005treatment groups

Vehiclecontrol
group

EEpopulation(n = 41)

EE50population(n = 20)

EEpopulation(n = 26)

EE50population(n = 15)

Mean OSDI Score at Baseline

50.0 Points

31.1 Points

49.8 Points

35.0 Points

Mean Change in OSDI from Baseline to Week Six

18.0 Points

12.7 Points

15.3 Points

11.1 Points

Percentage Change in OSDI Score from Baseline to Week Six

36%

41%

31%

32%

The graphs below set forth
with respect to each of the combined EBI-005 treatment groups and the vehicle control group in the total efficacy evaluable population and in the EE50 population, the mean change in OSDI scores from baseline at each evaluation visit following
randomization during the treatment period.

Retrospective
AnalysisPainful or Sore Eyes Question on OSDI. In the total efficacy evaluable population and in patients in the EE50 population, we observed an improvement on the OSDI question regarding painful or sore eyes at
week six from baseline in the combined EBI-005 treatment groups. We also observed that the trend in the improvement in the score on the OSDI question regarding painful or sore eyes from baseline at week six favoring the combined EBI-005 treatment
groups compared to the improvement in the score on the OSDI question regarding painful or sore eyes from baseline at week six in the vehicle control group was greater in the EE50 population than in the total efficacy evaluable population.

The table below sets forth with respect to each
of the combined EBI-005 treatment groups and the vehicle control group in the total efficacy evaluable population and in the EE50 population:



the mean score on the OSDI question regarding painful or sore eyes at baseline;

the mean change in score on the OSDI question regarding painful or sore eyes from baseline at week six; and



the percentage change in score on the OSDI question regarding painful or sore eyes from baseline at week six.

Painful or sore eyes question

Combined EBI-005treatment groups

Vehiclecontrol
group

EEpopulation(n = 41)

EE50population(n = 20)

EEpopulation(n = 26)

EE50population(n = 15)

Mean Score on OSDI Question at Baseline

1.8 Points

1.4 Points

1.7 Points

1.3 Points

Mean Change in Score on OSDI Question from Baseline to Week Six

0.9 Points

0.9 Points

0.5 Points

0.4 Points

Percentage Change in Score on OSDI Question from Baseline to Week Six

46%

61%

27%

31%

The graphs below set forth
with respect to each of the combined EBI-005 treatment groups and the vehicle control group in the total efficacy evaluable population and in the EE50 population, the mean change in scores on the OSDI question regarding painful or sore eyes from
baseline at each evaluation visit following randomization during the treatment period.

On most of the other
individual OSDI questions, we observed trends in changes in scores at week six from baseline that favored patients treated with EBI-005 compared to patients treated with vehicle control in an analysis of the efficacy evaluable population. On eight
of the other OSDI questions, we observed trends in changes in scores at week six from baseline that favored patients treated with EBI-005 compared to vehicle control in an analysis of the efficacy evaluable population. On the other three OSDI
questions, we observed trends in changes in scores at week six from baseline that favored vehicle control compared to patients treated with EBI-005 in an analysis of the efficacy evaluable population. However, none of these trends were statistically
significant.

Retrospective
AnalysisCFS. In the total efficacy evaluable population and in patients in the EE50 population, we observed an improvement in CFS at week six from baseline in the combined EBI-005 treatment groups. We also
observed in the EE50 population a strong trend in the improvement in the CFS score from

baseline at week six favoring the combined EBI-005 treatment groups compared to improvement in the CFS score from baseline at week six in the vehicle control group. We did not observe this trend
in the total efficacy evaluable population.

The
table below sets forth with respect to each of the combined EBI-005 treatment groups and the vehicle control group in the total efficacy evaluable population and in the EE50 population:



the mean total CFS score at baseline;



the mean change in total CFS score from baseline at week six; and



the percentage change in total CFS score from baseline at week six.

CFS score

Combined EBI-005treatment groups

Vehiclecontrol
group

EEpopulation(n = 41)

EE50population(n = 20)

EEpopulation(n = 26)

EE50population(n = 15)

Mean Total CFS Score at Baseline

9.0 Points

8.9 Points

9.0 Points

8.4 Points

Mean Change in Total CFS Score from Baseline at Week Six

3.0 Points

3.5 Points

2.7 Points

2.3 Points

Percent Change in Total CFS Score from Baseline at Week Six

33%

39%

30%

28%

The graphs below set forth
with respect to each of the combined EBI-005 treatment groups and the vehicle control group in the total efficacy evaluable population and in the EE50 population, the mean change in total CFS scores from baseline at each evaluation visit following
randomization during the treatment period.

Pre-Specified
Exploratory EndpointArtificial Tear Use

We distributed artificial tears to patients in this trial with one dose per vial. Patients were permitted to use up to four vials of these artificial tears daily. Patients were instructed not to use any
other artificial tears during this trial. At the end of the trial, we counted the number of vials used by each patient. We excluded from our assessment of artificial tear use in the combined EBI-005 treatment groups one patient for whom there were
no records of use of artificial tears. In addition, we performed a statistical outlier assessment of artificial tear use and excluded from our assessment of the combined EBI-005 treatment groups one patient whose use of artificial tears

was many times greater than any other patient and whose inclusion could distort any statistical analysis. All of the results presented on the use of artificial tears excluded these two patients
from the combined EBI-005 treatment groups.

The
use of artificial tears was similar at baseline for patients in the combined EBI-005 treatment groups and vehicle control groups. However, over the course of the six-week treatment period of this trial, we observed the following differences, which
were statistically significant only with respect to the efficacy evaluable population:



the mean artificial tear usage was greater in the vehicle control group than in the combined EBI-005 treatment groups in the total efficacy evaluable
population (p=0.005) and in the EE50 population (p=0.190);



the median artificial tear usage was higher in the vehicle control group than in the combined EBI-005 treatment groups in the total efficacy evaluable
population and in the EE50 population; and



a greater percentage of patients in the vehicle control group used large amounts of artificial tears, which we defined as the use of more than 50 vials
during this trial, than in the combined EBI-005 treatment groups in the total efficacy evaluable population (p=0.005) and in the EE50 population (p=0.267).

The table below sets forth with respect to each of the
combined EBI-005 treatment groups and the vehicle control group in the total efficacy evaluable population and in the EE50 population:



the mean number of vials of artificial tears used;



the median number of vials of artificial tears used; and



the percentage of patients who used large amounts of artificial tears.